Retroviral protease inhibitors

ABSTRACT

HIV protease inhibitors are disclosed which are characterized as having both hydroxyethylamine and N-heterocyclic moieties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/625,384,filed Jul. 26, 2000, now allowed, which is a continuation of applicationSer. No. 09/348,711, filed Jul. 7, 1999, now abandoned, which is anon-provisional application of Ser. No. 60/092,090 filed Jul. 8, 1998,each of which is hereby incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to retroviral protease inhibitors and,more particularly relates to novel compounds and a composition andmethod for inhibiting retroviral proteases. This invention, inparticular, relates to N-heterocyclic moiety containinghydroxyethylamine protease inhibitor compounds, a composition and methodfor inhibiting retroviral proteases such as human immunodeficiency virus(HIV) protease and for treatment or prophylaxis of a retroviralinfection, e.g., an HIV infection. The subject invention also relates toprocesses for making such compounds as well as to intermediates usefulin such processes.

2. Related Art

During the replication cycle of retroviruses, gag and gag-poll geneproducts are translated as proteins. These proteins are subsequentlyprocessed by a virally encoded protease (or proteinase) to yield viralenzymes and structural proteins of the virus core. Most commonly, thegag precursor proteins are processed into the core proteins and the pollprecursor proteins are processed into the viral enzymes, e.g., reversetranscriptase and retroviral protease. It has been shown that correctprocessing of the precursor proteins by the retroviral protease isnecessary for assembly of infectious virons. For example, it has beenshown that frameshift mutations in the protease region of the poll geneof HIV prevents processing of the gag precursor protein. It has alsobeen shown through site-directed mutagenesis of an aspartic acid residuein the HIV protease that processing of the gag precursor protein isprevented. Thus, attempts have been made to inhibit viral replication byinhibiting the action of retroviral proteases.

Retroviral protease inhibition typically involves a transition statemimetic whereby the retroviral protease is exposed to a mimetic compoundwhich binds (typically in a reversible manner) to the enzyme incompetition with the gag and gag-poll proteins to thereby inhibitreplication of structural proteins and, more importantly, the retroviralprotease itself. In this manner, retroviral proteases can be effectivelyinhibited.

Several classes of mimetic compounds are known to be useful asinhibitors of the proteolytic enzyme renin. See, for example, U.S. Pat.No. 4,599,198; G.B. 2,184,730; G.B. 2,209,752; EP 0 264 795; G.B.2,200,115 and U.S. SIR H₇₂₅. Of these, G.B. 2,200,115; G.B. 2,209,752;EP 0 264,795; U.S. SIR H₇₂₅; and U.S. Pat. No. 4,599,198 disclose ureacontaining hydroxyethylamine renin inhibitors.

However, it is known that, although renin and HIV proteases are bothclassified as aspartyl proteases, compounds which are effective renininhibitors generally cannot be predicted to be effective HIV proteaseinhibitors.

Several classes of mimetic compounds have been proposed, particularlyfor inhibition of proteases, such as for inhibition of HIV protease.Such mimetics include hydroxyethylamine isoteres and reduced amideisosteres. See, for example, EP 0 346 847; EP 0 342,541; Roberts et al,“Rational Design of Peptide Based Proteinase Inhibitors, “Science, 248,358 (1990); and Erickson et al, “Design, Activity, and 2.8 A CrystalStructure of a C₂ Symmetric Inhibitor Complexed to HIV-1 Protease,”Science, 249, 527 (1990). EP 0 346 847 and U.S. Pat. No. 5,648,364disclose certain N-heterocyclic moiety-containing hydroxyethylamineprotease inhibitor compounds, but do not suggest or disclose those ofthe present invention. WO 95/09843, WO 96/28464, U.S. Pat. No.5,484,926, U.S. Pat. No. 5,705,500, U.S. Pat. No. 5,756,533, U.S. Pat.No. 5,776,971 and Kaldor, Stephen W., “A systematic Study of P₁-P₃Spanning Sidechains for the Inhibition of HIV-1 Protease”, Bioorganicand Medicinal Chemistry Letters, 5, 715-720 (1995) disclose arylthiolcontaining hydroxyethylamine isosteres incorporated into HIV-proteaseinhibitors but do not suggest or disclose the compounds of the presentinvention.

While it has been suggested that no improvement in the in vitro or exvivo potency of hydroxyethylamine based inhibitors of HIV-proteasecontaining a P₂ asparagine can be made (Science, Roberts et al.), thisis not the case. Improvements over P₂ asparagine containing inhibitorsare made. The moieties reported herein are expected to permit certainallowances over the aforementioned reference including proteolyticstability, duration of action in vivo and pharmacokinetic profile.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to virus inhibiting compounds andcompositions. More particularly, the present invention is directed toretroviral protease inhibiting compounds and compositions, to a methodof inhibiting retroviral proteases, to processes for preparing thecompounds and to intermediates useful in such processes. The subjectcompounds are characterized as N-heterocyclic moiety containinghydroxyethylamine inhibitor compounds.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, there are provided severalnovel retroviral protease inhibiting compounds or a pharmaceuticallyacceptable salt, prodrug or ester thereof.

A preferred class of retroviral inhibitor compounds of the presentinvention are those represented by the formula:

or a pharmaceutically acceptable salt, prodrug or ester thereof,wherein:

-   R represents hydrogen, alkoxycarbonyl, aryloxycarbonylalkyl,    aralkoxycarbonyl, alkylcarbonyl, cycloalkylcarbonyl,    cycloalkylalkoxycarbonyl, cycloalkylalkanoyl, alkanoyl, aralkanoyl,    aroyl, aryloxycarbanoyl, aryloxyalkanoyl, heterocyclylcarbonyl,    heterocycloxycarbonyl, heteroaralkoxycarbonyl, heterocyclylalkanoyl,    heterocyclylalkoxycarbonyl, heteroarylcarbonyl,    heteroaryloxycarbonyl, heteroaroyl, alkyl, alkenyl, cycloalkyl,    aryl, aralkyl, aryloxyalkyl, heteroaryloxyalkyl, hydroxyalkyl,    aralkylaminoalkylcarbonyl, aminoalkanoyl, aminocarbonyl,    aminocarbonylalkyl, alkylaminoalkylcarbonyl, and mono- and    disubstituted aminocarbonyl and aminoalkanoyl radicals wherein the    substituents are selected from the group consisting of alkyl, aryl,    aralkyl, cycloalkyl, cycloalkylalkyl, heteroaryl, heteroaralkyl,    heterocycloalkyl, alkoxycarbonyl, arylalkyloxycarbonyl and    heterocycloalkylalkyl radicals, or in the case of disubstituted    aminoalkanoyl, said substituents along with the nitrogen atom to    which they are attached form a heterocyclyl or heteroaryl radical;-   R′ represents radicals defined for R³, or R and R′ together with the    nitrogen to which they are attached form a heterocycloalkyl or    heteroaryl radical;-   R¹ represents hydrogen, —CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂,    —C(O)NHCH₃, —C(O)N(CH₃)₂, —CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl,    alkylthioalkyl, thiolalkyl and the corresponding sulfoxide and    sulfone derivatives thereof, alkenyl, alkynyl, haloalkyl,    alkoxyalkyl and cycloalkyl radicals and amino acid side chains    selected from the group consisting of asparagine, S-methyl cysteine    and the corresponding sulfoxide and sulfone derivatives thereof,    glycine, leucine, isoleucine, allo-isoleucine, tert-leucine,    alanine, phenylalanine, ornithine, histidine, norleucine, glutamine,    valine, threonine, allo-threonine, serine, aspartic acid and    beta-cyano alanine, side chains;-   R² represents alkylthioalkyl, cycloalkylthioalkyl or arylthioalkyl    radicals, which radicals are optionally substituted with a    substituent selected from the group consisting of —NO₂, —OR¹⁵,    —SR¹⁵, and halogen radicals, wherein R¹⁵ represents hydrogen and    alkyl radicals;-   R³ represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl,    hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl,    heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl,    and heteroaralkyl radicals;-   Y′ represents O, S and NR³;-   R⁴ and R⁵ together with the nitrogen atom to which they are bonded    represent a N-heterocycle; and R⁶ represents hydrogen and alkyl    radicals.

Another class of preferred inhibitor compounds of the present inventionare those represented by the formula:

or a pharmaceutically acceptable salt, prodrug or ester thereof,wherein:

-   R′ represents radicals defined for R³;-   t represents either 0 or 1;-   R¹ represents hydrogen, —CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂,    —C(O)NHCH₃, —C(O)N(CH₃)₂, —CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl,    alkylthioalkyl, thioalkyl and the corresponding sulfoxide and    sulfone derivatives thereof, alkenyl, alkynyl, alkoxyalkyl,    haloalkyl and cycloalkyl radicals and amino acid side chains    selected from the group consisting of asparagine, S-methyl cysteine    and the corresponding sulfoxide and sulfone derivatives thereof,    glycine, leucine, isoleucine, allo-isoleucine, tert-leucine,    alanine, phenylalanine, ornithine, histidine, norleucine, glutamine,    valine, threonine, allo-threonine, serine, aspartic acid and    beta-cyano alanine side chains;-   R² represents alkylthioalkyl, cycloalkylthioalkyl or arylthioalkyl    radicals, which radicals are optionally substituted with a    substituent selected from the group consisting of —NO₂, —OR¹⁵,    —SR¹⁵, and halogen radicals, wherein R's represents hydrogen and    alkyl radicals;-   R³ represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl,    hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl,    heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl,    and heteroaralkyl radicals;-   Y′ represents O, S and NR³;-   R⁴ and R⁵ together with the nitrogen atom to which they are bonded    represent a N-heterocycle;-   R⁶ represents hydrogen and alkyl radicals;-   and R²⁰ and R²¹ represent radicals as defined for R¹.

Yet another preferred class of compounds of the present invention arethose represented by the formula:

or a pharmaceutically acceptable salt, prodrug or ester thereof,wherein:

-   t represents either 0 or 1;-   R¹ represents hydrogen, —CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂,    —C(O)NHCH₃, —C(O)N(CH₃)₂, —CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl,    thioalkyl, thioalkyl and the corresponding sulfoxide and sulfone    derivatives thereof, alkenyl, alkynyl, alkoxyalkyl, haloalkyl and    cycloalkyl radicals and amino acid side chains selected from the    group consisting of asparagine, S-methyl cysteine and the    corresponding sulfoxide and sulfone derivatives thereof, glycine,    leucine, isoleucine, allo-isoleucine, tert-leucine, alanine,    phenylalanine, ornithine, histidine, norleucine, glutamine, valine,    threonine, allo-threonine, serine, aspartic acid and beta-cyano    alanine side chains;-   R² represents alkylthioalkyl, cycloalkylthioalkyl, or arylthioalkyl    radicals, which radicals are optionally substituted with a    substituent selected from the group consisting of —NO₂, —OR¹⁵,    —SR¹⁵, and halogen radicals, wherein R¹⁵ represents hydrogen and    alkyl radicals;-   R³ represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl,    hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl,    heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl,    and heteroaralkyl radicals;-   X′ represent O, N and C(R¹⁷) where R¹⁷ represents hydrogen and alkyl    radicals;-   Y′ and Y″ independently represent O, S and NR³;-   R⁴ and R⁵ together with the nitrogen atom to which they are bonded    represent a N-heterocycle;-   R⁶ represents hydrogen and alkyl radicals;-   R³⁰, R³¹ and R³² independently represent radicals as defined for R¹,    or one of R¹ and R³⁰ together with one of R³¹ and R³² and the carbon    atoms to which they are attached form a cycloalkyl radical; and-   R³³ and R³⁴ independently represent radicals as defined for R³, or    R³³ and R³⁴ together with X′ represent cycloalkyl, aryl,    heterocyclyl and heteroaryl radicals, provided that when X′ is O,    R¹⁴ is absent.

Still another preferred class of compounds of the present invention arethose represented by the formula:

or a pharmaceutically acceptable salt, prodrug or ester thereof,wherein:

-   R represents hydrogen, alkoxycarbonyl, aryloxycarbonylalkyl,    aralkoxycarbonyl, alkylcarbonyl, cycloalkylcarbonyl,    cycloalkylalkoxycarbonyl, cycloalkylalkanoyl, alkanoyl, aralkanoyl,    aroyl, aryloxycarbanoyl, aryloxyalkanoyl, heterocyclylcarbonyl,    heterocycloxycarbonyl, heteroaralkoxycarbonyl, heterocyclylalkanoyl,    heterocyclylalkoxycarbonyl, heteroarylcarbonyl,    heteroaryloxycarbonyl, heteroaroyl, alkyl, alkenyl, cycloalkyl,    aryl, aralkyl, aryloxyalkyl, heteroaryloxyalkyl, hydroxyalkyl,    aralkylaminoalkylcarbonyl, aminoalkanoyl, aminocarbonyl,    aminocarbonylalkyl, alkylaminoalkylcarbonyl, and mono- and    disubstituted aminocarbonyl and aminoalkanoyl radicals wherein the    substituents are selected from the group consisting of alkyl, aryl,    aralkyl, cycloalkyl, cycloalkylalkyl, heteroaryl, heteroaralkyl,    heterocycloalkyl, and heterocycloalkylalkyl radicals, or in the case    of disubstituted aminoalkanoyl, said substituents along with the    nitrogen atom to which they are attached form a heterocyclyl or    heteroaryl radical;-   R′ represents radicals defined for R³, or R and R′ together with the    nitrogen to which they are attached form a heterocycloalkyl or    heteroaryl radical; n represents 1 or 2;-   R¹ represents hydrogen, —CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂,    —C(O)NHCH₃, —C(O)N(CH₃)₂, —CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl,    alkylthioalkyl, thioalkyl and the corresponding sulfoxide and    sulfone derivatives thereof, alkenyl, alkynyl, haloalkyl,    alkoxyalkyl and cycloalkyl radicals and amino acid side chains    selected from the group consisting of asparagine, S-methyl cysteine    and the corresponding sulfoxide and sulfone derivatives thereof,    glycine, leucine, isoleucine, allo-isoleucine, tert-leucine,    alanine, phenylalanine, ornithine, histidine, norleucine, glutamine,    valine, threonine, allo-threonine, serine, aspartic acid and    beta-cyano alanine side chains;-   R^(1′) and R^(1″) independently represent hydrogen and radicals as    defined for R³;-   R² represents alkylthioalkyl, cycloalkylthioalkyl, or arylthioalkyl    radicals, which radicals are optionally substituted with a    substituent selected from the group consisting of —NO₂, —OR¹⁵,    —SR¹⁵, and halogen radicals, wherein R¹⁵ represents hydrogen and    alkyl radicals;-   R² represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl,    hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl,    heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl,    and heteroaralkyl radicals;-   Y′ and Y″ independently represent O, S and NR³;-   R⁴ and R⁵ together with the nitrogen atom to which they are bonded    represent a N-heterocycle;-   R⁶ and R^(6′) independently represent hydrogen and alkyl radicals.

Another class of preferred inhibitor compounds of the present inventionare those represented by the formula:

or a pharmaceutically acceptable salt, prodrug or ester thereof,wherein:

-   R′ represents radicals defined for R³, or R and R′ together with the    nitrogen to which they are attached form a heterocycloalkyl or    heteroaryl radical;-   t represents either 0 or 1;-   R¹ represents hydrogen, —CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂,    —C(O)NHCH₃, —C(O)N(CH₃)₂, —CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl,    alkylthioalkyl, thioalkyl and the corresponding sulfoxide and    sulfone derivatives thereof, alkenyl, alkynyl and cycloalkyl    radicals and amino acid side chains selected from the group    consisting of asparagine, S-methyl cysteine and the corresponding    sulfoxide and sulfone derivatives thereof, glycine, leucine,    isoleucine, allo-isoleucine, tert-leucine, alanine, phenylalanine,    ornithine, histidine, norleucine, glutamine, valine, threonine,    allo-threonine, serine, aspartic acid and beta-cyano alanine side    chains;-   R² represents alkylthioalkyl, cycloalkylthioalkyl or arylthioalkyl    radicals, which radicals are optionally substituted with a    substituent selected from the group consisting of —NO₂, —OR¹⁵,    —SR¹⁵, and halogen radicals, wherein R¹⁵ represents hydrogen and    alkyl radicals;-   R³ represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl,    hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl,    heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl,    and heteroaralkyl radicals;-   Y′ represents O, S and NR³;-   R⁴ and R⁵ together with the nitrogen atom to which they are bonded    represent a N-heterocycle;-   R⁶ represents hydrogen and alkyl radicals;-   R³³ and R³⁴ independently represent radicals as defined for R³, or    R³³ and R³⁴ together with the nitrogen to which they are attached    form heterocyclyl and heteroaryl radicals;-   and R²⁰ and R²¹ represent radicals as defined for R¹.

As utilized herein, the term “alkyl”, alone or in combination, means astraight-chain or branched-chain alkyl radical containing from 1 toabout 10, preferably from 1 to about 8, carbon atoms. Examples of suchradicals include methyl, ethyl, n-propyl, iso-propyl, n-butyl, isobutyl,sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, octyl and the like. Theterm “thioalkyl” means an alkyl radical having at least one sulfur atom,wherein alkyl has the significance given above. An example of athioalkyl is —C(CH₃)₂SCH₃. The corresponding sulfoxide and sulfone ofthis thioalkyl are —C(CH₃)₂S(O)CH₃ and (CH₃)₂S(O)₂CH₃, respectively. Theterm “alkenyl”, alone or in combination, means a straight-chain orbranched-chain hydrocarbon radial having one or more double bonds andcontaining from 2 to about 18 carbon atoms preferably from 2 to about 8carbon atoms. Examples of suitable alkenyl radicals include ethenyl,propenyl, allyl, 1,4-butadienyl and the like. The term “alkynyl”, aloneor in combination, means a straight-chain hydrocarbon radical having oneor more triple bonds and containing from 2 to about 10 carbon atoms.Examples of alkynyl radicals include ethynyl, propynyl (propargyl),butynyl and the like. The term “alkoxy”, alone or in combination, meansan allyl ether radical wherein the term alkyl is as defined above.Examples of suitable alkyl ether radicals include methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy andthe like. The term “cycloalkyl”, alone or in combination, means an alkylradical which contains from about 3 to about 8 carbon atoms and iscyclic. Examples of such cycloalkyl radicals include cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl and the like. The term“cycloalkylalkyl” means an alkyl radical as defined above which issubstituted by a cycloalkyl radical containing from about 3 to about 8,preferably from about 3 to about 6, carbon atoms. The term “aryl”, aloneor in combination, means a phenyl or naphthyl radical which optionallycarries one or more substituents selected from alkyl, alkoxy, halogen,hydroxy, amino, nitro and the like, such as phenyl (CH₅H₅), p-tolyl,4-methoxyphenyl, 4-(tert-butoxy)phenyl, 4-fluorophenyl, 4-chlorophenyl,4-hydroxyphenyl, 2-hydroxyphenyl, 4-nitrophenyl, 2-nitrophenyl,1-naphthyl, 2-naphthyl, and the like. The term “aralkyl”, alone or incombination, means an alkyl radical as defined above in which onehydrogen atom is replaced by an aryl radical as defined above, such asbenzyl, 2-phenylethyl and the like. The term “aralkoxy carbonyl”, aloneor in combination, means a radical of the formula —C(═O)—O— aralkyl inwhich the term “aralkyl” has the significance given above. An example ofan aralkoxycarbonyl radical is benzyloxycarbonyl. The term “aryloxy”,alone or in combination, means a radical of the formula aryl-O— in whichthe term “aryl” has the significance given above. The term “alkanoyl,alone or in combination, means an acyl radical derived from analkanecarboxylic acid, examples of which include acetyl, propionyl,butyryl, valeryl, 4-methylvaleryl, and the like. The term“cycloalkylcarbonyl” means an acyl group derived from a monocyclic orbridged cycloalkanecarboxylic acid such as cyclopropanecarbonyl,cyclohexanecarbonyl, adamantanecarbonyl, and the like, or from abenz-fused monocyclic cycloalknecarboxylic acid which is optionallysubstituted by, for example, alkanoylamino, such as1,2,3,4-tetrahydro-2-naphthoyl,2-acetamido-1,2,3,4-tetrahydro-2-naphthoyl. The term “aralkanoyl” meansan acyl radical derived from an aryl-substituted alkanecarboxylic acidsuch as phenylacetyl, 3-phenylpropionyl (hydrocinnamoyl),4-phenylbutyryl, (2-naphthyl)acetyl, 4-chlorohydrocinnamoyl,4-aminohydrocinnamoyl, 4-methoxyhydrocinnamoyl, and the like. The term“aroyl” means an acyl radical derived from an aromatic carboxylic acid.Examples of such radicals include aromatic carboxylic acids, anoptionally substituted benzoic or naphthoic acid such as benzoyl,4-chlorobenzoyl, 4-carboxybenzoyl, 4-(benzyloxycarbonyl)benzoyl,1-naphthoyl, 2-naphthoyl, 6-carboxy-2-naphthoyl,6-(benzyloxycarbonyl)-2-naphthoyl, 3-benzyloxy-2-naphthoyl,3-hydroxy-2-naphthoyl, 3-(benzyloxyformamido)-2-naphthoyl, and the like.The term “arylthioalkyl” (aryl-5-alkyl) means an aryl radical as definedabove attached to a sulfur atom that is attached to an alkyl radical asis defined above and with the preferred alkyl group being 1 to 3 carbonatoms inclusive and the preferred aryl ring being 6 to 10 carbon atomsinclusive and with the oxidation states of sulfur including the sulfide(—S—), sulfoxide (—S(O)—), or sulfone(—S(O)₂—), with the preferredoxidation state of the sulfur being that of the sulfide (—S—). Mostpreferred is an aryl ring of 6 carbon atoms. The term “alkylthioalkyl”means an alkyl group of 1 to 6 carbon atoms inclusive bonded to a sulfuratom witch is bonded to an alkyl group of 1 to 3 carbon atoms inclusive.The heterocyclyl or heterocycloalkyl portion of a heterocyclylcarbonyl,heterocyclyloxycarbonyl, heterocyclylalkoxycarbonyl, orheterocyclylalkyl group or the like is a saturated or partiallyunsaturated monocyclic, bicyclic or tricyclic heterocycle which containsone or more hetero atoms selected from nitrogen, oxygen and sulphur,which is optionally substituted on one or more carbon atoms by halogen,alkyl, alkoxy, oxo, and the like, and/or on a secondary nitrogen atom(i.e., —NH—) by alkyl, aralkoxycarbonyl, alkanoyl, phenyl or phenylalkylor on a tertiary nitrogen atom (i.e. ═N—) by oxido and which is attachedvia a carbon atom. The heteroaryl portion of a heteroaroyl,heteroaryloxycarbonyl, or heteroaralkoxycarbonyl group or the like is anaromatic monocyclic, bicyclic, or tricyclic heterocyle which containsthe hetero atoms and is optionally substituted as defined above withrespect to the definition of heterocyclyl. Examples of such heterocyclyland heteroaryl groups are pyrrolidinyl, piperidinyl, piperazinyl,morpholinyl, thiamorpholinyl, pyrrolyl, imidazolyl (e.g., imidazol-4-yl,1-benzyloxycarbonylimidazol-4-yl, etc.), pyrazolyl, pyridyl, pyrazinyl,pyrimidinyl, furyl, tetrahydrofuryl, tetrahydrothienyl, thienyl,triazolyl, oxazolyl, thiazolyl, indolyl (e.g., 2-indolyl, etc.),quinolinyl (e.g., 2-quinolinyl, 3-quinolinyl, 1-oxido-2-quinolinyl,etc.), isoquinolinyl (e.g., 1-isoquinolinyl, 3-isoquinolinyl, etc.),tetrahydroquinolinyl (e.g., 1,2,3,4-tetrahydro-2-quinolinyl, etc.),1,2,3,4-tetrahydroisoquinolinyl(e.g.,1,2,3,4-tetrahydro-1-oxo-isoquinolinyl, etc.), quinoxalinyl,beta-carbolinyl, 2-benzofurancarbonyl, 1-, 2-, 4- or 5-benzimidazolyl,benzofuryl, tetrahydrobenzofuryl and the like. Heteroaryl or heterocycyl(heterocyclo, heterocycle) groups may be bonded through a heteroatom orcarbon. The term “cycloalkylalkoxycarbonyl” means an acyl group derivedfrom a cycloalkylalkoxycarboxylic acid of the formulacycloalkylalkyl-O—CO—OH wherein cycloalkylalkyl has the significancegiven above. The term “aryloxyalkanoyl” means an acyl radical of theformula aryl-O-alkanoyl wherein aryl and alkanoyl have the significancegiven above. The term “heterocyclylalkanoyl” is an acyl radical derivedfrom a heterocyclyl-substituted alkane carboxylic acid whereinheterocyclyl has the significance given above. The term“heterocyclyloxycarbonyl” means an acyl group derived fromheterocyclyl-O—CO—OH wherein heterocyclyl is as defined above. The term“heterocyclylalkanoyl” means an acyl radical of the formulaheterocyclyl-alkanoyl wherein heterocyclyl and alkanoyl have thesignificance given above. The term “heterocyclylalkoxycarbonyl” means anacyl radical derived from heterocyclyl-substituted alkane-O—CO—OHwherein heterocyclyl has the significance given above. The term“heteroaryloxycarbonyl” means an acyl radical derived from a carboxylicacid represented by heteroaryl-O—COOH wherein heteroaryl has thesignificance given above. The term “aminocarbonyl” alone or incombination, means an amino-substituted carbonyl (carbamoyl) groupderived from an amino-substituted carboxylic acid (carbamic acid)N—(C═O)— wherein the amino group can be a primary, secondary or tertiaryamino group containing substituents selected from hydrogen, alkyl, aryl,aralkyl, cycloalkyl, cycloalkylalkyl radicals and the like. The term“aminoalkanoyl” means an acyl radical derived from an amino substitutedalkanecarboxylic acid wherein the amino group can be a primary,secondary or tertiary amino group containing substituents selected fromthe group consisting of hydrogen, cycloalkyl, cycloalkylalkyl radicalsand the like, examples of which include N-methylaminoacetyl,N-cyclopropylaminoacetyl, N-methoxyethylaminoacetyl, pyrrolidinyacetyl,N,N-dimethylaminoacetyl and N-benzylaminoacetyl. The term “halogen”means fluorine, chlorine, bromine or iodine. The term haloalkyl means analkyl group substituted with one or more halogen atoms on one ordifferent carbons such as chloromethyl, chlorobromoethyl,trifluoromethyl, 2,2,2-trifluoromethylethylene and the like. The term“leaving group” generally refers to groups readily displaceable by anucleophile, such as an amine, a thiol or an alcohol nucleophile. Suchleaving groups are well known and include carboxylates,N-hydroxysuccinimide, N-hydroxybenzotriazole, halides, triflates,tosylates, —OR and —SR and the like. Preferred leaving groups areindicated herein where appropriate. The term hydroxypropylenediaminemeans hydroxyethylamine when applied to this class of proteaseinhibitors. The term “N-heterocyclic moiety” or N-heterocycle is aheterocyclic radical or heterocycle bonded via its nitrogen or with anitrogen atom radical bond site which may be a heterocycloalkyl orheteroaryl, wherein heterocycloalkyl and heteroaryl have thesignificance given above, with the addition that polycyclic heteroarylmay be fully aromatic or partially aromatic, for example, a fusedheterocycloalkylaryl and a fused heteroarylcycloalkyl, and theheterocycloalkyl and cycloalkyl may also be bridged. Preferably, theN-heterocyclic moiety has 5, 6 or 7 members when monocyclic; 5, 6 or 7members in a ring with 1, 2 or 3 members in a bridge when a bridgedmonocyclic; 11, 12 or 13 members when bicyclic; and 11 to 16 memberswhen tricyclic. Examples of N-heterocyclic moieties include, but are notlimited to, those represented by the following formulae:

wherein:

-   R⁹ represents hydrogen, alkyl, alkoxycarbonyl, monoalkylcarbamoyl,    monoaralkylcarbamoyl, monoarylcarbamoyl or a group of the formula:-   R¹⁰ and R¹¹ each represents alkyl;-   R¹² represents hydrogen, hydroxy, alkoxycarbonylamino or acylamino;-   R¹³ represents hydrogen, alkyl, aryl, alkoxycarbonyl or acyl;-   m is 1, 2, 3, or 4;-   p is 1 or 2; and-   q is 0, 1 or 2.

The term prodrug means esters and amide derivatives of amines, acids,alcohols, thiols and the like that are able to be converted in vitro orin vivo by chemical or biochemical or metabolic processed into an activeparent compound. A prodrug may or may not have intrinsic biologicalactivity.

Procedures for preparing the compounds of Formulas I-IV are set forthbelow. It should be noted that the general procedures are shown as itrelates to preparation of compounds having a specified stereochemistry,for example, wherein the stereochemistry about the hydroxyl group isdesignated as (R). However, such procedures are generally applicable tothose compounds of opposite configuration, e.g., where thestereochemistry about the hydroxyl group is (S) or (RS). The terms (R)and (S) configuration are as defined by the IUPAC 1974 Recommendationsfor Section E, Fundamental Stereochemistry, Pure Appl. Chem. (1976) 45,13-30. The documents WO 95/09843, U.S. Pat. No. 5,484,926, Kaldor,Stephen W., “A systematic Study of P₁-P₃ Spanning Sidechains for theInhibition of HIV-1 Protease”, Bioorganic and Medicinal ChemistryLetters, 5, 715-720 (1995), WO 96/28463, WO 96/28418, WO 96/28465, WO96/22287, EP 0 346 847, U.S. Pat. No. 5,648,364, WO 96/28464, U.S. Pat.No. 5,521,219, U.S. Pat. No. 5,463,104, U.S. Pat. No. 5,843,946, U.S.Pat. No. 5,756,533, U.S. Pat. No. 5,776,971 and U.S. Pat. No. 5,705,500include supplementary or alternative methods for preparing intermediatesor compounds useful or possibly useful for preparing compounds of thisinvention as required or desired by a person of ordinary skill in theart which documents are incorporated herein by reference.

Preparation of Compounds of Formula I

The compounds of the present invention represented by formula I throughIV above wherein R² is alkylthioalkyl or arylthioalkyl (ArSCH₂—) can beprepared utilizing the following general procedures as illustrated insome cases with compounds wherein R² is arylalkyl. An N-protectedhaloketone derivative of an amino acid having the formula:

wherein P represents an amino protecting group, R² is as defined aboveand Z represents a chlorine, bromine or iodine atom, is reduced to thecorresponding alcohol utilizing an appropriate reducing agent. Suitableamino protecting groups are well known in the art and includecarbobenzoxy, butyryl, t-butoxycarbonyl, acetyl, benzoyl and the like.Preferred amino protecting groups are carbobenzoxy and t-butoxycarbonyl.A preferred N-protected haloketone is a compound of Formula VIII whereinP is benzyloxycarbonyl (Z or CBZ), R² is phenylthioalkyl and the alkylgroup has one carbon atom. A preferred reducing agent is sodiumborohydride. The reduction reaction is conducted at a temperature offrom −10° C. to about 25° C., preferably at about 0° C., in a suitablesolvent system such as, for example, tetrahydrofuran, and the like. TheN-protected haloketones may be commercially available from Bachem, Inc.,Torrance, Calif. Alternatively, the haloketones can be prepared by theprocedure set forth in S. J. Pittkau, J. Prakt. Chem., 315, 1037 (1973),and subsequently N-protected utilizing procedures which are well knownin the art.

The resulting alcohol is then reacted, preferably at room temperature,with a suitable base in a suitable solvent system to produce anN-protected amino epoxide of the formula:

wherein P and R² are as defined above. Suitable solvent systems forpreparing the amino epoxide include methanol, ethanol, isopropanol,tetrahydrofuran, dioxane, and the like including mixtures thereof.Suitable bases for producing the epoxide from the reduced haloketoneinclude potassium hydroxide, sodium hydroxide, potassium t-butoxide, DBUand the like. A preferred base is potassium hydroxide.

Alternatively, a protected amino epoxide can be prepared starting withan D, L or DL-amino acid (illustrated below with an L-aminoacid) whichis reacted with a suitable amino- and carboxyl-protecting groups in asuitable solvent to produce an amino-protected L-amino acid ester of theformula:

wherein P¹ and P² independently represent hydrogen and amino-protectinggroups as defined above with respect to P, provided that P¹ and P² arenot both hydrogen: P⁴ represents hydrogen and a carboxy-protectinggroup, preferably one which is also an amino-protecting group as definedabove with respect to P; and R² is as defined above.

The amino protected L-amino acid ester is then reduced, to thecorresponding alcohol. For example, the amino-protected L-amino acidester can be reduced with diisobutylaluminum hydride at −78° C. in asuitable solvent such as toluene. The resulting alcohol is thenconverted, by way of a Swern Oxidation, to the corresponding aldehyde ofthe formula:

wherein P¹, p² and R³ are as defined above. Thus, a dichloromethanesolution of the alcohol is added to a cooled (−75 to −68° C.) solutionof oxalyl chloride in dichloromethane and DMSO in dichloromethane andstirred for 35 minutes.

The aldehyde resulting from the Swern Oxidation is then reacted with ahalomethyllithium reagent, which reagent is generated in situ byreacting an alkyl lithium or aryl lithium compound with a dihalomethanerepresented by the formula X¹CH₂X² wherein X¹ and x² independentlyrepresent I, Br or Cl. For example, a solution of the aldehyde andchloroiodomethane in THF is cooled to −78° C. and a solution of n-butyllithium in hexane is added. The resulting product is a mixture ofdiastereomers of the corresponding amino-protected epoxides of theformulas:

The diastereomers can be separated by chromatography or, alternatively,once reacted in subsequent steps the distereomeric products can beseparated.

The amino epoxide is then reacted, in a suitable solvent system, with anequivalent or more amount, of a heterocycle of the formula:  HNR⁴R⁵wherein R⁴ and R⁵ are as defined above. The reaction can be conductedover a wide range of temperatures, e.g., from about 60° C. to about 120°C. in an inert organic solvent, but is preferably, but not necessarily,conducted at a temperature at which the solvent begins to reflux.Suitable solvent systems include those wherein the solvent is analcohol, such as methanol, ethanol, isopropanol, and the like, etherssuch as tetrahydrofuran, dioxane and the like, toluene,N,N-dimethylformamide, dimethylsulfoxide, and mixtures thereof. Apreferred solvent is isopropanol. Non-limiting examples of heterocyclescorresponding to the formula HNR⁴R⁵ include those having the followingformula:

wherein

-   R⁹, R¹⁰, R¹¹, R¹², R¹³, m, p and q have the significance given    above, and the like. The resulting product is a 3-(N-protected    amino)-3-(R²)-1-(NR⁴R⁵)-propan-2-ol derivative (hereinafter referred    to as an amino alcohol) is an intermediate which contains the    desired N-heterocyclic moiety or intermediate thereof and can be    represented by the formula:    wherein p¹, p², R², R⁴ and R⁵ are as described above.

Alternatively, the compounds of the present invention represented byFormula I above can be prepared utilizing the following generalprocedure. An N-protected haloketone derivative of an amino acid havingthe formula:

wherein P, P¹ and P² represent amino protecting groups, R² is as definedabove, and Z represents a chlorine, bromine or iodine atom, is reacted,in a suitable inert organic solvent system, with an equal or greaterequivalent amount, of a desired amine of the formula:HNR⁴R⁵wherein R⁴ and R⁵ are as defined above. The reaction yields a compoundof the general formula:

wherein p¹, p², R², R⁴ and R⁵ have the significance given earlier.

The reaction of the N-protected haloketone derivative of an amino acid,preferably one in which one of P¹ and/or p² represent benzyloxy carbonyland one of P¹ and/or p² represent hydrogen, with the desired amine, aheterocyclic compound of formula HNR⁴R⁵, can be carried out in any knownmanner, for example, in an inert organic solvent such as halogenatedaliphatic hydrocarbon (e.g. dichloromethane, N,N-dimethylformamide,tetrahydrofuran, isopropanol and ethanol) and in the presence of a base(e.g. a trialkylamine such as triethylamine and diisopropylethyl amine,sodium bicarbonate, DBU and the like), conveniently at about roomtemperature.

The reduction of the aminoketone compound of Formula V results in acompound of the general formula:

wherein p¹, p², R², R⁴ and R⁵ have the significance given earlier. Thereduction of the aminoketone compound of Formula V to the N-heterocyclicmoiety-containing derivative (Formula VI) can be carried out accordingto known methods for the reduction of a carbonyl group to a hydroxygroup. Thus, for example, the reduction can be carried out using acomplex metal hydride such as an alkali metal borohydride, especiallysodium borohydride, in an appropriate organic solvent such as alkanol(e.g. methanol, ethanol, propanol, isopropanol etc.).

Conveniently, the reduction is carried out at about room temperature.

Following preparation of the N-heterocyclic moiety-containingderivative, the amino protecting group P is, or P¹ and p² are, removedunder conditions which will not affect the remaining portion of themolecule. These methods are well known in the art and include acidhydrolysis, hydrogenolysis and the like. A preferred method involvesremoval of the protecting group, e.g., removal of a carbobenzoxy group,by hydrogenolysis utilizing palladium on carbon in a suitable solventsystem such as an alcohol, acetic acid, and the like or mixturesthereof. Where the protecting group is N,N-dibenzyl, these groups may beremoved by hydrogenolysis utilizing palladium on carbon. Where theprotecting group is a t-butoxycarbonyl group, it can be removedutilizing an inorganic or organic acid, e.g., HCl or trifluoroaceticacid, in a suitable solvent system, e.g., dioxane or methylene chloride.The resulting product is the amine salt derivative. Followingneutralization of the salt, the amine is then reacted with an amino acidor corresponding derivative thereof represented by the formula(RR¹NCH(R¹)COOH) or (RR¹N[CR^(1′)R^(1″)]CH(R¹)COOH) wherein R^(1′),R^(1″) and R¹ are as defined above and may be P and/or P¹ and/or P² toproduce the antiviral compounds of the present invention having theformula:

wherein P, R¹, R^(1′), R^(1″), R², R⁴ and R⁵ are as defined above.Preferred protecting groups in this instance are a benzyloxycarbonylgroup or a t-butoxycarbonyl group. Where the amine is reacted with aderivative of an amino acid and R^(1′) and R^(1″) are both hydrogen, sothat the amino acid is a, beta-amino acid, such, beta-amino acids can beprepared according to the procedure set forth in copending applications,U.S. Ser. No. 07/836,163 Method of Preparing Optically Active,beta-Amino Acids; filed Feb. 14, 1992; Docket No. 07-21(855)A) (acontinuation of U.S. Ser. No. 07/706,508, now abandoned, which is acontinuation of U.S. Ser. No. 07/345,808, now abandoned). Where one ofR^(1′) and R^(1′) is hydrogen and R¹ is hydrogen so that the amino acidis a homo-beta-amino acid, such homo-beta-amino acids can be preparedaccording to the procedure set forth in copending application, U.S. Ser.No. 07/853,561 (Method of Preparing Optically Active Homo-beta-AminoAcids; filed; Docket No. 07-21(722)A). The process thereof preserves thechirality of the starting succinates. The method thereof involves Curtisrearrangement of chiral 3-mono-substituted succinates (succinic acidhalf ester) of sufficient purity to exhibit optical activity. The Curtisrearrangement is preferably effected by treating a chiral3-mono-substituted succinate with one equivalent of diphenoxyphosphorylazide (PhO)₂PON₃ and triethylamine to form an acyl azide followed byheating in an inert solvent, such as warm toluene, preferably at about80° C. for about three hours to afford an isocyanate derivative which issubsequently hydrolyzed to give amines. The 3-mono-substitutedsuccinates can be prepared by a procedure analogous to that described inU.S. Pat. No. 4,939,288, filed Jan. 23, 1989, which is herebyincorporated by reference. The alpha-amino acid compounds are preparedusing, for example, methods in U.S. Pat. No. 5,483,946, or variationswell know in the art. It should be noted that compounds of thisinvention can be prepared in stepwise as is shown by the example inScheme 1 and Scheme 2 herein below or via a convergent synthesis whereparts of the final product are made separately and coupled in a finalstep to produce said final product of this invention. The person skilledin the art will select the appropriate process based on compound to bemade under particular conditions at that particular time or location.

Coupling conditions such as mixed anhydride reaction, activated estercoupling with, for example, hydroxybenzotriazol (HOBT) and the like arevery well know in the art especially the aminoacid and peptide synthesisand reaction art.

The N-protecting group can be subsequently removed, if desired,utilizing the procedures described above, and then reacted with acarboxylate represented by the formula:

wherein R is as defined above and L is an appropriate leaving group suchas a halide. Examples of such carboxylates include acetylchloride,phenoxyacetyl chloride, benzoyl chloride, 2-naphthyloxycarbonyl chlorideand 2-benzofurancarbonyl chloride. A solution of the free amine (oramine acetate salt) and about 1.0 equivalent of the carboxylate aremixed in an appropriate solvent system and optionally treated with up tofive equivalents of a base such as, for example, N-methylmorpholine, atabout room temperature. Appropriate solvent systems includetetrahydrofuran, methylene chloride or N,N-dimethylformamide, and thelike, including mixtures thereof.

Alternatively, a sulfonyl-containing compound represented by theformula:

wherein R is as defined above and L is an appropriate leaving group suchas halide may be substituted for the aforementioned carboxylate.Preparation of Compounds of Formula II

A mercaptan of the formula R′SH is reacted with a substitutedmethacrylate of the formula:

by way of a Michael Addition. The Michael Addition is conducted in asuitable solvent and in the presence of a suitable base, to produce thecorresponding thiol derivative represented by the formula:

wherein R′ and R¹ represent radicals defined above; R²⁰ and R²¹represent hydrogen and radicals as defined for R¹; and R²² representsalkyl, aryl or aralkyl, preferably R²² is methyl, ethyl, t-butyl orbenzyl. Suitable solvents in which the Michael Addition can be conductedinclude alcohols such as, for example, methanol, ethanol, butanol andthe like, as well as ethers, e.g., THF, and acetonitrile, DMF, DMSO, andthe like, including mixtures thereof. Suitable bases include Group Imetal alkoxides such as, for example sodium methoxide, sodium ethoxide,sodium butoxide and the like as well as Group I metal hydrides, such assodium hydride, including mixtures thereof.

The thiol derivative is converted into the corresponding sulfone of theformula:

by oxidizing the thiol derivative with a suitable oxidation agent in asuitable solvent. Suitable oxidation agents include, for example,hydrogen peroxide, sodium meta-perborate, potassium peroxy monosulfate,meta-chloroperoxybenzeic acid, and the like, including mixtures thereof.Suitable solvents include acetic acid (for sodium meta-perborate) and,for other peracids, ethers such as THP and dioxane, and acetonitrile,DME and the like, including mixtures thereof.

The sulfone is then converted to the corresponding free acid of theformula:

utilizing a suitable base, e.g., lithium hydroxide, sodium hydroxide,and the like, including mixtures thereof, in a suitable solvent, suchas, for example, THF, acetonitrile, DMF, DMSO, methylene chloride andthe like, including mixtures thereof. When R²² is benzyl, the free acidmay be obtained by hydrogenolysis over palladium on carbon.

The free acid is then coupled, utilizing, as described above, procedureswell known in the art, to the N-heterocyclic moiety-containingderivative of an amino alcohol which is described above for thepreparation of compounds of Formula I. The resulting product is acompound represented by Formula II.

Alternatively, one can couple the N-heterocyclic moiety-containingderivative to the commercially available acid,

remove the thioacetyl group with a suitable base, such as hydroxide, oran amine, or ammonia, and then react the resulting thiol with analkylating agent, such as an alkyl halide, tosylate or mesylate toafford compounds at the following structure:

The sulfur can then be oxidized to the corresponding sulfone usingsuitable oxidizing agents, as described above, to afford the desiredcompounds of the following structure:

Alternatively, to prepare compounds of Formula II, a substitutedmethacrylate of the formula:

wherein L represents a leaving group as previously defined, R³⁵ and R³⁶represent hydrogen and radicals as defined for R¹; and R³⁷ representsalkyl, aralkyl, cycloalkyl and cycloalkylalkyl radicals, is reacted witha suitable sulfonating agent, such as, for example, a sulfinic acidrepresented by the formula R′SO₂M, wherein R′ represents radicals asdefined above and M represents a metal adapted to form a salt of theacid, e.g., sodium, to produce the corresponding sulfone represented bythe formula:

wherein R′, R³⁵, R³⁶ and R³⁷ are as defined above. The sulfone is thenhydrolyzed in the presence of a suitable base, such as lithiumhydroxide, sodium hydroxide and the like, to the compound represented bythe formula:

wherein R′, R³⁵ and R³⁶ represent radicals as defined above. Theresulting compound is then asymmetrically hydrogenated utilizing anasymmetric hydrogenation such as, for example, a ruthenium-BINAP complexto produce the reduced product, substantially enriched in the moreactive isomer represented by the formula:

wherein R′, R³⁵ and R³⁶ represent radicals as defined above. Where themore active isomer has the R-stereochemistry, a Ru(R-BINAP) asymmetrichydrogenation catalyst can be utilized. Conversely, where the moreactive isomer has the S-stereochemistry, a Ru(S-BINAP) catalyst can beutilized. Where both isomers are active, or where it is desired to havea mixture of the two diastereomers, a hydrogenation catalyst such asplatinum, or palladium on carbon can be utilized to reduce the abovecompound. The reduced compound is then coupled to the N-heterocyclicmoiety-containing derivative, as described above, to produce compoundsof Formula II.

Alternatively, one can prepare the preferred2(S)-methyl-3-(methylsulfonyl)propionic acid according to the schemeoutlined below starting from commercially availableD-(−)-S-benzyoyl-beta-mercaptoisobutyric acid tert-butyl ester.Treatment of D-(−)-S-benzoyl-beta-mercaptoisobutyric acid tert-butylester with a methanolic ammonia solution resulted in the formation ofD-(−)-beta-mercaptoisobutyric acid tert-butyl ester and benzamide. Thefree mercaptan thus produced was freed from the benzamide by filtrationand then further purified by crystallization. Treatment ofD-(−)-beta-mercaptoisobutyric acid tert-butyl ester with methyl iodidein the presence of a suitable base such as1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) results in the formation of thecorresponding thioether S-methyl-D-(−)-beta-mercaptoisobutyric acidtert-butylester in excellent yield. The thioether is then oxidized witha suitable oxidant such as sodium metaperborate in acetic acid to givethe corresponding sulfone. Specifically,S-methyl-D-(−)-beta-mercaptoisobutyric acid tert-butyl ester is treatedwith sodium perborate in acetic acid to produce2(S)-methyl-3-(methylsulfonyl)propionic acid tert-butyl ester inexcellent yield. The tert-butyl ester can then selectively removed bytreatment with 4N hydrochloric acid in dioxane to produce2(S)-methyl-3-(methylsulfonyl)propionic acid as a crystalline acid invery good yield. It is envisioned that variations of the sulfur andcarboxylate protecting groups would be acceptable for preparation of2(S)-methyl-3-(methylsulfonyl)propionic acid and analogs.

Preparation of Compounds of Formula III

To produce compounds of Formula III, starting with a lactate of formula:

wherein P represents alkyl and aralkyl radicals, such as, for example,ethyl, methyl, benzyl and the like. The hydroxyl group of the lactate isprotected as its ketal by reaction in a suitable solvent system withmethyl isopropenyl ether (1,2-methoxypropene) in the presence of asuitable acid. Suitable solvent systems include methylene chloride,tetrahydrofuran and the like as well as mixtures thereof. Suitable acidsinclude POCl₃ and the like. It should be noted that well-known groupsother than methyl isopropenyl ether can be utilized to form the ketal.The ketal is then reduced with diisobutyhluminum hydride (DIBAL) at −78°C. to produce the corresponding aldehyde which is then treated withethylidenetriphenylphosphorane (Wittig reaction) to produce a compoundrepresented by the formula:

The ketal protecting group is then removed utilizing procedureswell-known in the art such as by mild acid hydrolysis. The resultingcompound is then esterified with isobutyryl chloride to produce acompound of the formula:

This compound is then treated with lithium diisopropyl amide at −78° C.followed by warming of the reaction mixture to room temperature toeffect a Claisen rearrangement ([3,3]) to produce the corresponding acidrepresented by the formula:

Treatment of the acid with benzyl bromide (BnBr) in the presence of atertiary amine base, e.g., DBU, produces the corresponding ester whichis then cleaved oxidatively to give a trisubstituted succinic acid:

The trisubstituted succinic acid is then coupled to the N-heterocyclicmoiety-containing derivative as described above. To produce the freeacid, the benzyl ester is removed by hydrogenolysis to produce thecorresponding acid. The acid can then be converted to the primary amideby methods well-known in the art.

An alternative method for preparing trisubstituted succinic acidsinvolves reacting an ester of acetoacetic acid represented by theformula:

where R is a suitable protecting group, such as methyl, ethyl, benzyl ort-butyl with sodium hydride and a hydrocarbyl halide (R³¹X or R³²X) in asuitable solvent, e.g., THF, to produce the corresponding disubstitutedderivative represented by the formula:

This disubstituted acetoacetic acid derivative is then treated withlithium diisopropyl amide at about −10° C. and in the presence ofPhN(triflate)₂ to produce a vinyl triflate of the formula:

The vinyl triflate is then carbonylated utilizing a palladium catalyst,e.g., Pd(OAc)₂(Ph₃)P, in the presence of an alcohol (R″OH) or water(R″═H) and a base, e.g., triethylamine, in a suitable solvent such asDMF, to produce the olefinic ester or acid of the formula:

The olefin can then be subsequently asymmetrically hydrogenated, asdescribed above, to produce a trisubstituted succinic acid derivative ofthe formula:

If R″ is not H, R″ can be removed by either hydrolysis, acidolysis, orhydrogenolysis, to afford the corresponding acid, which is then coupledto the N-heterocyclic moiety-containing derivative as described aboveand then, optionally, the R group removed to produce the correspondingacid, and optionally, converted to the amide.

Alternatively, one can react the N-heterocyclic moiety-containingderivative with either a suitably monoprotected succinic acid orglutaric acid of the following structures;

followed by removal of the protecting group and conversion of theresulting acid to an amide. One can also react an anhydride of thefollowing structure:

with the N-heterocyclic moiety-containing derivative and then separateany isomers or convert the resulting acid to an amide and then separateany isomers.

It is contemplated that for preparing compounds of the Formulas havingR⁶ being other than hydrogen, the compounds can be prepared followingthe procedure set forth above and, prior to coupling the N-heterocyclicmoiety-containing derivative to the respective acid, the derivativecarried through a procedure referred to in the art as reductiveamination. Thus, a sodium cyanoborohydride and an appropriate aldehyde,such as formaldehyde, acetaldehyde and the like, can be reacted with theN-heterocyclic moiety-containing derivative compound at room temperaturein order to reductively aminate any of the compounds of Formulas I-IV.

Contemplated equivalents of the respective general formulas set forthabove for the antiviral compounds and derivatives as well as theintermediates are compounds otherwise corresponding thereto and havingthe same general properties wherein one or more of the various R groupsare simple variations of the substituents as defined therein, e.g.,wherein R is a higher alkyl group than that indicated. In addition,where a substituent is designated as, or can be, a hydrogen, the exactchemical nature of a substituent which is other than hydrogen at thatposition, e.g., a hydrocarbyl radical or a halogen, hydroxy, amino andthe like functional group, is not critical so long as it does notadversely affect the overall activity and/or synthesis procedure.

Optically active compound isomers as well as mixed or non-opticallyactive compound isomers are specifically intended to be included in thisdiscussion and in this invention. Examples of isomers are RS isomers,enantiomers, diastereomers, racemates, cis isomers, trans isomers, Eisomers, Z isomers, syn-isomers, anti-isomers, tautomers and the like.Aryl, heterocyclo or heteroaryl tautomers, heteroatom isomers and ortho,meta or para substitution isomers are also included as isomers. Solvatesor solvent addition compounds such as hydrates or alcoholates are alsospecifically included both as chemicals of this invention and in, forexample, formulations or pharmaceutical compositions for delivery. Inthe propylene diamine (hydroxyethylamine) function, a preferredconfiguration for the carbon bearing hydroxyl is R when theconfiguration at the carbon bearing the phenylthiomethylene group is R.A preferred set of isomers includes those depicted in the compounds ofExamples 21 through 34 inclusive.

The chemical reactions described above are generally disclosed in termsof their broadest application to the preparation of the compounds ofthis invention. Occasionally, the reactions may not be applicable asdescribed to each compound included within the disclosed scope. Thecompounds for which this occurs will be readily recognized by thoseskilled in the art. In all such cases, either the reactions can besuccessfully performed by conventional modifications known to thoseskilled in the art, e.g., by appropriate protection of interferinggroups, by changing to alternative conventional reagents, by routinemodification of reaction conditions, and the like, or other reactionsdisclosed herein or otherwise conventional, will be applicable to thepreparation of the corresponding compounds of this invention. In allpreparative methods, all starting materials are known or readilypreparable from known starting materials.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the following examples, melting points were determined on aFisher-Johns melting point apparatus and are uncorrected. All reagentswere used as received without purification. All proton and carbon NMRspectra were obtained on either a Varian VER-300 or VER-400 nuclearmagnetic resonance spectrometer using tetramethysilane as internalstandard. Gas chromatograph was performed on a Varian 3400chromatography system. All instruments were utilized according to themanufacturer's directions.

EXAMPLE 1 Preparation ofN-Benzyloxycarbonyl-3(S)-amino-1,2(S)-epoxy-4-phenylbutane

Part A

To a solution of 75.0 g (0.226 mol) ofN-benzyloxycarbonyl-L-phenylalanine chloromethyl ketone in a mixture of807 mL of methanol and 807 mL of tetrahydrofuran at −2° C., was added13.17 g (0.348 mol, 1.54 equiv.) of solid sodium borohydride over onehundred minutes. The solvents were removed in vacuo at 40° C. and theresidue dissolved in ethyl acetate (approx. 1 L). The solution waswashed sequentially with 1M potassium hydrogen sulfate, saturated sodiumbicarbonate and then saturated sodium chloride solutions. After dryingover anhydrous magnesium sulfate and filtering, the solution was removedin vacuo. To the resulting oil was added hexane (approx. 1 L) and themixture warmed to 60° C. with swirling. After cooling to roomtemperature, the solids were collected and washed with 2 L of hexane.The resulting solid was recrystallized from hot ethyl acetate and hexaneto afford 32.3 g (43% yield) ofN-benzyloxycarbonyl-3(S)-amino-1-chlorophenyl-2(S)-butanol, mp 150-151°C. and M+Li⁺=340. formula:

Part B

To a solution of 6.52 g (0.116 mol, 1.2 equiv.) of potassium hydroxidein 968 mL of absolute ethanol at room temperature, was added 32.3 g(0.097 mol) of N-CBZ-3(S)-amino-1-chloro-4-phenyl-2(S)-butanol, whereinCBZ stands for benzyloxycarbonyl. After stirring for fifteen minutes,the solvent was removed in vacuo and the solids dissolved in methylenechloride. After washing with water, drying over magnesium sulfate(MgSO₄), filtering and stripping, one obtains 27.9 g of a white solid.Recrystallization from hot ethyl acetate and hexane afforded 22.3 g (77%yield) of N-benzyloxycarbonyl-3(S)-amino-1,2(S)-epoxy-4-phenylbutane, mp102-103° C. and MH⁺ 298; formula:

EXAMPLE 2

Preparation of carbamic acid,[3-[3-[[(1,1-dimethylethyl)amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]-phenylmethylester, [3S-[2(1R*,2S*), 3α,4 aβ,8 aβ]]-. Also known as carbamic acid,[3-[3-[[(1,1-dimethylethyl)amino]carbonyl]decahydro-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]-,phenylmethyl ester, [3S-[2(1R*,2S*), 3α,4 aβ,8

Part A

L-tetrahydroisoquinoline-2-carboxylic acid (24.83 g, 0.140 mol) wassuspended in a solution of 80 mL of 2.5 N sodium hydroxide, 80 mL ofwater, and 80 mL of tetrahydrofuran. To this was added with vigorousstirring, 32.0 g (0.147 mol) of tert-butylpyrocarbonate in 20 mL oftetrahydrofuran. After 1 hour the pH dropped from 13 to 8.2, at pH 7.8sodium hydroxide (2.5 N) was added dropwise to maintain a pH of 8.8.After the pH stabilized, the contents were extracted with diethylether(2×125 mL). The aqueous phase was acidified (pH˜2.0) with more HCl,after cooling the solution in an ice bath. The precipitate was extractedwith ether, which was then dried over MgSO₄, fltered and concentrated toyield 36.8 grams of crude product which needed no purification (95%yield). The product wasN-tert-butoxycarbonyl-L-tetrahydroisoquinoline-2-carboxylic acid whichhas the following formula:

Part B

N-tert-butoxycarbonyl-L-tetrahydroisoquinoline-2-carboxylic acid (27.7g, 0.10 moles) was dissolved in 50 mL of dimethylformamide, and to thiswas added a warmed solution of 21 g of N-hydroxybenzotriazole in 30 mLof dimethylformamide. The solution was cooled to 10° C. and to this wasadded 19.1 g (0.10 moles) of1-(3-dimethylaminopropyl)-2-ethylcarbodiimide hydrochloride (EDC) andthe solution stirred for 10-15 minutes, at which time 7.3 g (0.100moles) of distilled tert-butylamine was added. After 14 hours thesolution was concentrated and 200 mL of ethyl acetate was added. Theorganic layer was washed with 5% aqueous potassium hydrogen sulfate,saturated sodium bicarbonate and brine, dried over magnesium sulfate,filtered, and concentrated to yield a yellow oil, which was crystallizedfrom warm hexane to yield 15.0 grams of a first crop (45.5% yield). Theproduct was N-tert-butoxycarbonyl-S-tetrahydroisoquinoline-2-carboxylicacid tert-butyl amide which has the following formula:

Part C

N-tert-butoxycarbonyl-5-tetrahydroisoquinoline-2-carboxylic acidtert-butyl amide (10.0 g, 30 mmol) was dissolved in 50 mL of methanoland placed in a Fisher Porter bottle with 3.2 g of wet rhodium (50 wt %H₂O, 10 wt % rhodium on carbon). The bottle was purged with nitrogen,and charged with 50 psig hydrogen and heated to 50° C. for 24 hours. Thecatalyst was removed by fltration and the methanol evaporated to yield amixture of (S,S,S) desired isomer and (S,R,R) undesired isomer in a 2:1ratio, respectively. The desired isomer (S,S,S) was separated by columnchromatography on silica gel using a 15-20% ethyl acetate hexanegradient elusion to yield 6.1 grams of pure isomer (66% yield). Theproduct wasN-tert-butyloxycarbonyl-(S,S,S)decahydroisoquinoline-2-carboxylic acid,tert-butylamide which has the following structure:

Part D

N-tert-butyloxycarbonyl-(S,S,S)decahydroisoquinoline-2-carboxylic acid,tert-butylamide (6.3 g, 18.6 mmol) was dissolved in 30 mL of 4N HCl indioxane and stirred under a nitrogen atmosphere for 1 hour. The solventwas removed and the white solid was suspended in 200 mL ofdichloromethane and washed several times with saturated sodiumbicarbonate. The dichloromethane (CH₂Cl₂) layer was dried over magnesiumsulfate, filtered, and concentrated to yield 3.68 g of freebase (85%yield). The amine product has the following stucture:

Part E

The amine from part D (3.68 g, 15.4 mmol) and 4.58 g (15.4 mmol) ofepoxide from Example 1 were dissolved in 50 mL of isopropanol andrefluxed under a nitrogen atmosphere for 48 hours. The isopropanol wasremoved and the crude solid was chromatographed on silica gel usingmethanol methylene chloride eluant to provide 8.0 g of pure product (97%yield) identified as carbamic acid,[3-[3-[[(1,1-dimethylethyl)amino]carbonyloctahyd-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)-propyl]-,phenylmethyl ester, [3S-(2(1R*,2S*), 3α,4 aβ,8 aβ]]-.

EXAMPLE 3 Alternate General Procedure for the Synthesis of1,3-Diamino-4-Phenyl-2-ol Derivatives

Step A:

A solution of L-phenylalanine (50.0 g, 0.302 mol), sodium hydroxide(24.2 g, 0.605 mol) and potassium carbonate (83.6 g, 0.605 mol) in water(500 mL) is heated to 97° C. Benzyl bromide (108.5 mL, 0.912 mol) isthen slowly added (addition time ˜25 minutes). The mixture is thenstirred at 97° C. for 30 minutes. The solution is cooled to roomtemperature and extracted with toluene (2×250 mL). The combined organiclayers are then washed with water, brine, dried over magnesium sulfate,filtered and concentrated to give an oil product. The crude product isthen used in the next step without purification.

Step B:

The crude benzylated product of the above step is dissolved in toluene(750 mL) and cooled to −55° C. A 1.5 M solution of DIBAL-H in toluene(443.9 mL, 0.666 mol) is then added at a rate to maintain thetemperature between −55° C. to −50° C. (addition time ˜1 hour). Themixture is stirred for 20 minutes at −55° C. The reaction is quenched at−55° C. by the slow addition of methanol (37 mL). The cold solution isthen poured into cold (5° C.) 1.5 N HCl solution (1.8 L). Theprecipitated solid (approx. 138 g) is filtered off and washed withtoluene. The solid material is suspended in a mixture of toluene (400mL) and water (100 mL). The mixture is cooled to 5° C., treated with 2.5N NaOH (186 mL) and then stirred at room temperature until the solid isdissolved. The toluene layer is separated from the aqueous phase andwashed with water and brine, dried over magnesium sulfate, filtered andconcentrated to a volume of 75 mL (89 g). Ethyl acetate (25 mL) andhexane (25 mL) are then added to the residue upon which the alcoholproduct begins to crystallize. After 30 minutes, an additional 50 mLhexane is added to promote further crystallization. The solid isfiltered off and washed with 50 mL hexane to give approximately 35 g ofmaterial. A second crop of material can be isolated by refiltering themother liquor. The solids are combined and recrystallized from ethylacetate (20 mL) and hexane (30 mL) to give, in 2 crops, approximately 40g (40% from L-phenylalanine) of analytically pure alcohol product. Themother liquors are combined and concentrated (34 g). The residue istreated with ethyl acetate and hexane which provides an additional 7 g(˜7% yield) of slightly impure solid product. Further optimization inthe recovery from the mother liquor is probable.

Step C:

A solution of oxalyl chloride (8.4 mL, 0.096 mol) in dichloromethane(240 mL) is cooled to −74° C. A solution of DMSO (12.0 mL, 0.155 mol) indichloromethane (50 mL) is then slowly added at a rate to maintain thetemperature at −74° C. (addition time ˜1.25 hours). The mixture isstirred for 5 minutes, followed by addition of a solution of the alcohol(0.074 mol) in 100 mL of dichloromethane (addition time ˜20 minutes,temp. −75° C. to −68° C.). The solution is stirred at −78° C. for 35minutes. Triethylamine (41.2 mL, 0.295 mol) is then added over 10minutes (temp. −780 to −68° C.) upon which the ammonium saltprecipitated. The cold mixture is stirred for 30 minutes and then water(225 mL) is added. The dichloromethane layer is separated from theaqueous phase and washed with water, brine, dried over magnesiumsulfate, filtered and concentrated. The residue is diluted with ethylacetate and hexane and then fltered to further remove the ammonium salt.The filtrate is concentrated to give the desired aldehyde product. Thealdehyde was carried on to the next step without purification.

Temperatures higher than −70° C. have been reported in the literaturefor the Swern oxidation. Other Swern modifications and alternatives tothe Swern oxidations are also possible.

A solution of the crude aldehyde 0.074 mol and chloroiodomethane (7.0mL, 0.096 mol) in tetrahydrofuran (285 mL) is cooled to −78° C. A 1.6 Msolution of n-butyllithium in hexane (25 mL, 0.040 mol) is then added ata rate to maintain the temperature at −75° C. (addition time ˜15minutes). After the first addition, additional chloroidomethane (1.6 mL,0.022 mol) is added again, followed by n-butyllithium (23 mL, 0.037mol), keeping the temperature at −75° C. The mixture is stirred for 15minutes. Each of the reagents, chloroiodomethane (0.70 mL, 0.010 mol)and n-butyllithium (5 mL, 0.008 mol) are added 4 more times over 45minutes at −75° C. The cooling bath is then removed and the solutionwarmed to 22° C. over 1.5 hours. The mixture is poured into 300 mL ofsaturated aq. ammonium chloride solution. The tetrahydrofuran layer isseparated. The aqueous phase is extracted with ethyl acetate (1×300 mL).The combined organic layers are washed with bane, dried over magnesiumsulfate, filtered and concentrated to give a brown oil (27.4 g). Theproduct could be used in the next step without purification. The desireddiastereomer can be purified by recrystallization at a subsequent step.Alternately, the product could be purified by chromatography.

The resulting epoxide can be substituted for the epoxide used in Example2, Part E.

β-Amino Acid Derivatives EXAMPLE 4 Preparation of carbamic acid,[3-[[3-[3-([(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenyl-methyl)propyl]amino]-2-methyl-3-oxopropyl]-,(4-methoxyphenyl)methyl ester, [3S-[2[1R*(S*),2S*],3α,4aβ,8aβ]]-

Part A

A solution of carbamic acid,[3-[3-[(1,1-dimethylethyl)amino]-carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)-propyl],phenylmethyl ester, [3S-[2(1R*,2S*),3α,4aβ,8aβ]]-(1.00 g, 1.87 mmol) inmethanol (50 mL) was hydrogenated in the presence of 0.50 g (50% wt) of10% Pd/charcoal for 19½ hours at room temperature and 50 psig of H₂ Thecatalyst was removed by vacuum filtration through a short plug of celiteand the solvent removed in vacuo to give 0.69 g (92%) of a white foam.Subsequently, the crude material was triturated with diethylether (Et₂O)to give 0.51 g (68%) of a white powder. The amine product has thefollowing formula:

Part B

N-p-methoxybenzyloxycarbonyl-α-methyl-β-alanine (430.5 mg, 1.6 mmol) wasdissolved in 2.0 mL of dimethyl formamide, and to this was added 326 mg(1.5 eq) of N-hydroxybenzotriazole and stirred until the solution washomogeneous. The solution was then cooled to 5° C. and 308 mg (1.6 mmol)of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide was added the reactionstirred for 20 minutes. A solution of 547 mg (1.6 mmol) of the aminefrom Part A in 5 mL of dimethylformamide (DMF) was added to the solutionand stirred for 16 hours. The dimethylformamide was removed by rotaryevaporation and replaced with ethyl acetate. The organic layer waswashed with water and saturated sodium bicarbonate, dried over magnesiumsulfate, filtered and concentrated to yield 730 mg of crude product.Flash column chromatography on silica gel using ethylacetate:dichloromethane:ethanol eluant 25:25:1 provided 250 mg ofproduct (25% yield), M+H=651, identified as carbamic acid,[3-[[3-[3-[[(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenyl-methyl)propyl]amino]-2-methyl-3-oxopropyl]-,(4-methoxyphenyl)methyl ester, [3S-[2[1R*(S*),2S*], 3α,4 aβ,8 aβ]]-.

EXAMPLE 5 Preparation of3-(4-methoxybenzyloxycarbonyl)amino-2(R)-methylpropionic acid also knownas N-4-Methoxybenzyloxycarbonyl-α-methyl-β-alanine (N-Moz-AMBA) andN-p-methoxybenzyloxyearbonyl-α-methyl-β-alanine

A. Preparation of 4(4-methoxybenzyl)itaconate

A 5 L three-necked round bottomed flask equipped with constant pressureaddition funnel, reflux condenser, nitrogen inlet, and mechanicalstirrer was charged with itaconic anhydride (660.8 g, 5.88 mol) andtoluene (2300 mL). The solution was warmed to reflux and treated with4-methoxybenzyl alcohol (812.4 g, 5.88 mol) dropwise over a 2.6 hourperiod. The solution was maintained at reflux for an additional 1.5 hrand then the contents were poured into three 2 L Erlenmeyer flasks tocrystallize. The solution was allowed to cool to room temperaturewhereupon the desired mono-ester crystallized. The product was isolatedby filtration on a Buchner funnel and air dried to give 850.2 g, 58%, ofmaterial with mp 83-85° C., a second crop, 17% was isolated aftercooling of the filtrate in an ice bath. ¹H NMR (CDCl₃) 300 MHz 7.32(d,J=8.7 Hz, 2H), 6.91(d, J=8.7 Hz, 2H), 6.49(s, 1H), 5.85(s, 1H), 5.12(s,2H), 3.83(s, 3H), 3.40(s, 2H).

B. Preparation of Methyl 4(4-methoxybenzyl! Itaconate

A 5 L three-necked round bottomed flask equipped with reflux condenser,nitrogen inlet, constant pressure addition funnel and mechanical stirrerwas charged with 4(4-methoxybenzyl) itaconate (453-4 g, 1.81 mol) andtreated with 1,5-diazabicyclo[4.3.0]non-5-ene (275.6 g, 1.81 mol),(DBN), dropwise so that the temperature did not rise above 15° C. Tothis stirring mixture was added a solution of methyl iodide (256.9 g,1.81 mol) in 250 mL of toluene from the dropping funnel over a 45 minuteperiod. The solution was allowed to warm to room temperature and stirredfor an additional 3.25 hours.

The precipitated DBN hydroiodide was removed by filtration, washed withtoluene and the filtrate poured into a separatory funnel. The solutionwas washed with saturated aqueous NaHCO₃ (2×500 mL), 0.2N HCl (1×500mL), and brine (2×500 ml), dried over anhyd. MgSO₄, fltered, and thesolvent removed in vacuo. This gave a clear colorless oil, 450.2 g, 94%whose NMR was consistent with the assigned structure. ¹H NMR (CDCl₃) 300MHz 7.30(d, J=8.7 Hz, 2H), 6.90(d, J=8.7 Hz, 2H), 6.34(s, 1H), 5.71(s,1H), 5.09(s, 2H), 3.82(s, 3H), 3.73(s, 3H), 3.38(s, 2H). ¹³C MMR (CDCl₃)170.46, 166.47, 159.51, 133.55, 129.97, 128.45, 127.72, 113.77, 66.36,55.12, 51.94, 37.64.

C. Preparation of Methyl 4(4-methoxybenzyl! 2(R)-methylsuccinate

A 500 mL Fisher-Porter bottle was charged with methyl4(4methoxybenzyl)itaconate (71.1 g, 0.269 mol), rhodium (R,R) DIPAMPcatalyst (204 mg, 0.269 mmol, 0.1 mol %) and degassed methanol (215 mL).The bottle was flushed 5 times with nitrogen and 5 times with hydrogento a final pressure of 40 psi. The hydrogenation commenced immediatelyand after ca. 1 hour the uptake began to taper off, after 3 hours thehydrogen uptake ceased and the bottle was flushed with nitrogen, openedand the contents concentrated on a rotary evaporator to give a brown oilthat was taken up in boiling iso-octane (ca. 200 mL, this was repeatedtwice), filtered through a pad of celite and the filtrate concentratedin vacuo to give 66.6 g, 93% of a clear colorless-oil, ¹H MMR (CDCl₃ 300MHz 7.30(d, j=8.7 Hz, 2H), 6.91(d, J=8.7 Hz, 2H), 5.08(s, 2H), 3.82(s,3H), 3.67(s, 3H), 2.95(ddq, J=5.7, 7.5, 8.7 Hz, 1H), 2.79(dd, J=8.1,16.5 Hz, 1H), 2.45(dd, J=5.7, 16.5 Hz, 1H), 1.23(d, J=7.5 Hz, 3H).

D. Preparation of Methyl 2(R)-methylsuccinate

A 3 L three-necked round-bottomed flask equipped with a nitrogen inlet,mechanical stirrer, reflux condenser and constant pressure additionfunnel was charged with methyl 4(4-methoxybenzyl) 2(R)-methylsuccinate(432.6 g, 1.65 mol) and toluene (1200 mL). The stirrer was started andthe solution treated with trifluoroacetic acid (600 mL) from thedropping funnel over 0.25 hours. The solution turned a deep purple colorand the internal temperature rose to 45° C. After stirring for 2.25hours the temperature was 27° C. and the solution had acquired a pinkcolor. The solution was concentrated on a rotary evaporator. The residuewas diluted with water (2200 mL) and sat. aq. NaHCO3 (1000 mL).Additional NaHCO₃ was added until the acid had been neutralized. Theaqueous phase was extracted with ethyl acetate (2×1000 mL) to remove theby-products and the aqueous layer was acidified to pH=1.8 with conc.HCl. This solution was extracted with ethyl acetate (4×1000 mL), washedwith brine, dried over anhyd. MgSO₄, f˜iltered and concentrated on arotary evaporator to give a colorless liquid 251 g, >100%, that wasvacuum distilled through a short path apparatus cut 1: bath temperature120° C. @ 1 mm, bp 25-29° C.; cut 2: bath temperature 140° C. @ 0.5 mm,bp 95-108° C., 151 g, [a]D @ 25° C.=+1.38° C. (c=15.475, MeOH),[a]D=+8.48° C. (neat); cut 3: bath temperature 140° C., bp 108° C., 36g, [a]D @ 25° C.=+1.49° C. (c=15.00, MeOH), [a]_(D)=+8.98° C. (neat).Cuts 2 and 3 were combined to give 189 g, 78% of product, ¹H NMR (CDCl₃)300 MHz 11.6(brs, 1H), 3.72(s, 3H), 2.92(ddq, J=5.7, 6.9, 8.0 Hz, 1H),2.81(dd, J=8.0, 16.8 Hz, 1H), 2.47(dd, J=5.7, 16.8 Hz, 1H), 1.26(d,J=6.9 Hz, 3H).

E. Preparation of Methyl Itaconate

A 50 mL round bottomed flask equipped with reflux condenser, nitrogeninlet and magnetic stir bar was charged with methyl 4(4-methoxybenzyl)itaconate (4.00 g, 16 mmol), 10 mL of toluene and 10 mL oftrifluoroacetic acid. The solution was kept at room temperature for 18hours and then the volatiles were removed in vacuo. The residue wastaken up in ethyl acetate and extracted three times with saturatedaqueous sodium bicarbonate solution. The combined aqueous extract wasacidified to pH=1 with aqueous potassium bisulfate and then extractedthree times with ethyl acetate. The combined ethyl acetate solution waswashed with saturated aqueous sodium chloride, dried over anhydrousmagnesium sulfate, filtered, and concentrated in vacuo. The residue wasthen vacuum distilled to give 1.23 g, 75% of pure product, bp 85-87 @0.1 mm. ¹H NMR (CDCl₃) 300 MHz 6.34(s, 1H), 5.73(s, 2H), 3.76(s, 3H),3.38(s, 2H). ¹³C NMR (CDCl₃) 177.03, 166.65, 129.220, 132.99, 52.27,37.46.

F. Curtius Rearrangement of Methyl 2(R)-methylsuccinate: Preparation ofMethyl N-Moz-α-methyl β-alanine

A 5 L four necked round bottomed flask equipped with a nitrogen inlet,reflux condenser, mechanical stirrer, constant pressure addition funnel,and thermometer adapter was charged with methyl 2(R)-methylsuccinate(184. la, 1.26 mol), triethylamine (165.6 g, 218 mL, 1.64 mol, 1.3equivalents), and toluene (1063 mL). The solution was warmed to 85° C.and then treated dropwise with a solution of diphenylphosphoryl azide(346.8 g, 1.26 mol) over a period of 1.2 hours. The solution wasmaintained at that temperature for an additional 1.0 hour and then themixture was treated with 4-methoxybenzyl alcohol (174.1 g, 1.26 mol)over a 0.33 hours period from the dropping funnel. The solution wasstirred at 88° C. for an additional 2.25 hours and then cooled to roomtemperature. The contents of the flask were poured into a separatoryfunnel and washed with saturated aqueous NaHCO₃ (2×500 mL), 0.2N HCl(2×500 mL), brine (1×500 mL), dried over anhydrous MgSO₄₁ fltered, andconcentrated in vacuo to give 302.3 g, 85% of the desired product as aslightly brown oil. ¹H NMR (CDCl₃) 300 MHz 7.32(d, J=8.4 Hz, 2H),6.91(d, J=8.4 Hz, 2H), 5.2(brm, 1H), 5.05(s, 2H), 3.83(s, 3H), 3.70(s,3H), 3.35(m, 2H), 2.70(m, 2H), 1.20(d, J=7.2 Hz, 3H).

G. Hydrolysis of Methyl N-Moz-α-methyl-β-alanine Preparation of α-methylβ-alanine Hydrochloride

A 5 L three-necked round bottomed flask equipped with a refluxcondenser, nitrogen inlet and mechanical stirrer was charged with methylN-Moz-α-methyl-α-alanine (218.6 g, 0.78 mol), glacial acetic acid (975mL) and 12N hydrochloric acid (1960 mL). The solution was then heated toreflux for 3 h. After the solution had cooled to room temperature (ca. 1hour) the aqueous phase was decanted from organic residue (polymer) andthe aqueous phase concentrated on a rotary evaporator. Upon addition ofacetone to the concentrated residue a slightly yellow solid formed thatwas slurried with acetone and the white solid was isolated by fltrationon a Buchner funnel The last traces of acetone were removed byevacuation to give 97.7 g, 90% of pure product, mp 128.5-130.5° C.[α]_(D) 25° C.=9.0° C. (c=2.535, Methanol). ¹H NMR (D2O) 300 MHz3.29(dd, J=8.6, 13.0 Hz, 1H), 3.16(dd, J=5.0, 13.0 m Hz, 1H), 2.94(ddq,J=7.2, 5.0, 8.6 Hz, 1H), 1.30(d,J=7.2 Hz, 3H); ¹³C NMR (D2O) 180.84,44.56, 40.27, 17.49.

H. Preparation of N-Boc α-Methyl-β-Alanine

A solution of α-Methyl-β-Alanine hydrochloride (97.7 g, 0.70 mol) inwater (1050 mL) and dioxane (1050 mL) the pH was adjusted to 8.9 with2.9N NaOH solution. This stirring solution was then treated withdi-tert-butyl pyrocarbonate (183.3 g, 0.84 mol, 1.2 equivalents) all atonce. The pH of the solution was maintained between 8.7 and 9.0 by theperiodic addition of 2.5N NaOH solution. After 2.5 h the pH hadstabilized and the reaction was judged to be complete. The solution wasconcentrated on a rotary evaporator (the temperature was maintained at<40° C.). The excess di-t-butyl pyrocarbonate was removed by extractionwith dichloromethane and then the aqueous solution was acidified withcold 1N HCl and immediately extracted with ethyl acetate (4×1000 mL).The combined ethyl acetate extract was washed with brine, dried overanhydrous MgSO₄, filtered and concentrated on a rotary evaporator togive a thick oil 127.3 g, 90% crude yield that was stirred with n-hexanewhereupon crystals of pure product formed, 95.65 g, 67%, mp 76-78° C.,[a]D @ 25° C.=−11.8° C. (c=2.4, EtOH). A second crop was obtained byconcentration of the filtrate and dilution with hexane, 15.4 g, for acombined yield of 111.05 g, 78%. ¹H NMR (acetone D6) 300 MHz 11.7 (brs,1H), 6.05 (brs 1H), 3.35 (m, 1H), 3.22 (m, 1H), 2.50 (m, 1H), 1.45(s,9H), 1.19 (d, J=7.3 Hz, 3H); ¹³C NMR (acetone D₆) 177.01, 79.28, 44.44,40.92, 29.08, 15.50. Elemental analysis calc'd. for C5H,7NO4: C, 53.19,H, 8.42; N, 6.89. Found: C, 53.36; H, 8.46; N, 6.99.

I. Preparation of N-4-Methoxybenzyloxycarbonyl-α-Methyl-β-Alanine

A solution of N-4-methoxybenzyloxycarbonyl-α-methyl-β-alanine methylester (2.81 g, 10.0 mmol) in 30 mL of 25% aqueous methanol was treatedwith lithium hydroxide (1.3 equivalents) at room temperature for aperiod of 2 hours. The solution was concentrated in vacuo and theresidue taken up in a mixture of water and ether and the phasesseparated and the organic phase discarded. The aqueous phase wasacidified with aqueous potassium hydrogen sulfate to pH=1.5 and thenextracted three times with ether. The combined ethereal phase was washedwith saturated aqueous sodium chloride solution, dried over anhydrousmagnesium sulfate, filtered and concentrated in vacuo to give 2.60 g,97% of N-4-methoxybenzyloxycarbonyl-α-methyl-β-alanine (N-Moz-AMBA)which was purified by recrystallization from a mixture of ethyl acetateand hexane to give 2.44 g, 91%, of pure product, mp 96-97° C., MH⁺=268.¹H NMR (D₆-acetone/300 MHz) 1.16 (3H, d, J=7.2 Hz), 2.70 (1H, m), 3.31(2H, m), 3.31 (3H, s), 4.99 (2H, s), 6.92 (2H, 4, J=8.7 Hz), 7.13 (2H,d, J=8.7 Hz).

Sulfone Derivatives EXAMPLE 6 Preparation of 3-Isoquinolinecarboxamide,N-(1,1-dimethylethyl)decahydro-2-[2-hydroxy-3-[[2-methyl-3-(methylsulfonyl)-1-oxopropyl]amino]-4-phenylbutyl]-,[3S-[2[2S*,3R*(R*)],3α,4aβ,8aβ]]-Part A

A solution of carbamic acid,[3-[3-[[(1,1-dimethylethyl)amino]-carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)-propyl]-phenylmethylester, [3S-[2(1R*,2S*), 3α,4aβ,8aβ]]-(1.00 g, 1.87 mmol) in methanol (50mL) was hydrogenated in the presence of 0.50 g (50% wt) of 10%Pd/charcoal for 19½ hours at room temperature and 50 psig of H₂. Thecatalyst was removed by vacuum filtration through a short plug of celiteand the solvent removed in vacuo to give 0.69 g (92%) of a white foam.Subsequently, the crude material was triturated with diethylether (Et₂O)to give 0.51 g (68%) of a white powder. The amine product has thefollowing formula:

Part B

To a solution of 230 mg (1.38 mmol) of2(S)-methyl-3-(methylsulfonyl)propionic acid in anhydrous DMF (4 mL) wasadded N-hydroxybenzotriazole (HOBt) (290 mg, 2.15 mmol) as a powder andEDC (390 mg, 2.03 mmol) as a powder. The resulting solution was stirredunder nitrogen for 10 minutes upon which was added 500 mg (1.24 mmol) ofamine from part A in DME (6 mL) and stirring continued for 17 hours.Subsequently, the reaction mixture was poured into 50% saturated NaHCO₃(aq) and chilled for 1 hour, upon which a pale precipitate formed, whichwas filtered, washed with water and dried under reduced pressure to give430 mg (63%) of a pale powder. The crude material was chromatographed onsilica, gel eluting with 5% ethanol in ethyl acetate to give 80 mg (12%)of 3-isoquinolinecarboxamide,N-(1,1-dimethylethyl)decahydro-2-[(2-hydroxy-3-[[2-methyl-3-(methylsulfonyl)-1-oxopropyl]amino]-4-phenylbutyl]-,[3S-[2[2S*,3R*(R*)],3α,4aβ,8aβ]]-as a white powder; mass spectrum, m/e 556 (FAB, M+Li).

The 2(S)-methyl-3-(methylsulfonyl)propionic acid (see Example 7 forpreparation) may be substituted by sulfonyl alkyl acids, far example,2-(R,S)methyl-3-(methylsulfonyl)propionic acid (see Example 8 forpreparation) and 2-(R,S)-methyl-3(β-phenethylsulfonyl)-propionic acid(see Example 9 for preparation)

EXAMPLE 7 Preparation of 2(S)-methyl-3-(methylsulfonyl)Propionic Acid

To a solution of 10 g of D-(−)-S-benzoyl-β-mercaptioisobutyric acidt-butyl ester in 20 mL of methanol was bubbled in gaseous ammonia at 0°C. The reaction was allowed to then warm to room temperature, stirredovernight and concentrated in vacuo. The resulting mixture of a solid(benzamide) and liquid was filtered to provide 5.21 g of a pale oilwhich then solidified. This was identified as2(S)-methyl-3-mercaptopropionic acid t-butyl ester:

To a solution of 5.21 g of 2(S)-methyl-3-mercaptopropionic acid t-butylester in 75 mL of toluene at 0° C. was added 4.50 g of1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1.94 mL of methyl iodide.After stirring at room temperature for 2.5 hours, the volatiles wereremoved, ethyl acetate added, washed with dilute hydrochloric acid,water, brine, dried and concentrated to afford 2.82 g of a pale oil,identified as 2(S)-methyl-3-(thiomethyl)propionic acid t-butyl ester:

To a solution of 2.82 g of 2(S)-methyl-3-(thiomethyl)propionic acidt-butyl ester in 50 mL of acetic acid was added 5.58 g of sodiumperborate and the mixture heated to 55° C. for 17 hours. The reactionwas poured into water, extracted with methylene chloride, washed withaqueous sodium bicarbonate, dried and concentrated to afford 2.68 g of2(S)-methyl-3-(methylsulfonyl)propionic acid t-butyl ester as a whitesolid:

To 2.68 g of 2(S)-methyl-3-(methylsulfonyl)propionic acid t-butyl esterwas added. 20 mL of 4N hydrochloric acid/dioxane and the mixture stirredat room temperature for 19 hours. The solvent was removed in vacuo toafford 2.18 g of crude product, which was recrystallized from ethylacetate/hexane to yield 1.44 g of2(S)-methyl-3-(methylsulfonyl)-propionic acid as white crystals:

EXAMPLE 8 Preparation of 2-(R,S)-Methyl-3-(methylsulfonyl)propionic acidby Asymmetric Hydrogenation

Part A

A solution of methyl 2-(bromomethyl)-acrylate (26.4 g, 0.148 mol) in 100mL of methanol was treated with sodium methanesulfinate (15.1 g, 0.148mol) portion wise over 10 minutes at room temperature. The solution wasthen stirred at room temperature for a period of 1.25 hours and thesolution concentrated in vacuo. The residue was then taken up in waterand extracted four times with ethyl acetate. The combined ethyl acetatesolution was washed with saturated sodium chloride, dried over anhydrousmagnesium sulfate, filtered and concentrated to give a white solid, 20.7g, which was taken up in boiling acetone/methyl t-butyl ether andallowed to stand whereupon crystals of pure methyl2-(methylsulfonylmethyl) acrylate 18.0 g, 68% formed, mp 65-68° C.Formula:

Part B

A solution of methyl 2-(methylsulfonylmethyl) acrylate (970 mg, 5.44mmol) in 15 mL of tetrahydrofuran was treated with a solution of lithiumhydroxide (270 mg, 6.4 mmol) in 7 mL of water. The solution was stirredat room temperature for 5 minutes and then acidified to pH=1 with 1 Naqueous potassium hydrogen sulfate and the solution extracted threetimes with ethyl acetate. The combined ethyl acetate solution was driedover anhydrous magnesium sulfate, filtered, and concentrated to give 793mg, 89% of 2-(methylsulfonylmethyl) acrylic acid, mp 147-149° C.;formula:

Part C

A solution of 2-(methylsulfonylmethyl) acrylic acid (700 mg, 4.26 mmol)in 20 mL of methanol was charged into a Fisher-Porter bottle along with10% palladium on carbon catalyst under a nitrogen atmosphere. Thereaction vessel was sealed and flushed five times with nitrogen and thenfive times with hydrogen. The pressure was maintained at 50 psig for 16hours and then the hydrogen was replaced with nitrogen and the solutionfiltered through a pad of celite to remove the catalyst and the filtrateconcentrated in vacuo to give 682 mg, 96%, of2-(R,S)methyl-3-methylsulfonyl propionic acid; formula:

EXAMPLE 9 Preparation of Sulfones by Michael Addition to MethylMethacrylate

Part A

A solution of methyl methacrylate (7.25 g, 72.5 mmol) and phenethylmercaptan (10.0 g, 72.5 mmol) in 100 mL of methanol was cooled in an icebath and treated with sodium methoxide (100 ma, 1.85 mmol). The solutionwas stirred under nitrogen for 3 hours and then concentrated in vacuo togive an oil that was taken up in ether and washed with 1 N aqueouspotassium hydrogen sulfate, saturated aqueous sodium chloride, driedover anhydrous magnesium sulfate, filtered and concentrated to give16.83 g, 97.5% of methyl 2-(R,S)-methyl-4-thia-6-phenyl hexanoate as anoil. TLC on SiO₂ eluting with 20:1 hexane:ethyl acetate (v:v) Rf=0.41.Formula:

Part B

A solution of methyl 2-(R,S)-methyl-thia-6-phenyl hexanoate (4.00 g,16.8 mmol) in 100 mL of dichloromethane was stirred at room temperatureand treated portion wise with meta-chloroperoxybenzoic acid (7.38 g,39.2 mmol) over approximately 40 minutes. The solution was stirred atroom temperature for 16 hours and then filtered and the filtrate washedwith saturated aqueous sodium bicarbonate, 1N sodium hydroxide,saturated aqueous sodium chloride, dried over anhydrous magnesiumsulfate, filtered, and concentrated to give 4.50 g, 99% of desiredsulfone. The unpurified sulfone was dissolved in 100 mL oftetrahydrofuran and treated with a solution of lithium hydroxide (1.04g, 24.5 mmol) in 40 mL of water. The solution was stirred at roomtemperature for 2 minutes and then concentrated in vacuo. The residuewas then acidified with 1N aqueous potassium hydrogen sulfate to pH=1and then extracted three times with ethyl acetate. The combined ethylacetate solution was washed with saturated aqueous sodium chloride,added over anhydrous magnesium sulfate, filtered and concentrated togive a white solid. The solid was taken up in boiling ethylacetate/hexane and allowed to stand undisturbed whereupon white needlesformed that were isolated by fltration and air added to give 3.38 g, 79%of 2-(R,S)methyl-3(˜-phenethylsulfonyl)-propionic acid, mp 91-93° C.;formula:

β-Asparagine Derivatives

EXAMPLE 10 Preparation of butanediamide,N⁴-[3-[3-[[(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]-2-[(2-quinolinylcarbonyl)amino]-,[3S[2[1R*(R*),2S*],3α,4aβ,8aβ]]-

Part A

A solution of carbamic acid,[3-[3-[[(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl],phenylmethyl ester, [3S-[2(1R*,2S*],3α,4aβ,8aβ]-(1.2 g, 2.2 mmol) in 50mL of methanol was charged to a Fisher Porter tube. The contents werepurged with nitrogen and 300 mg, 25 wt % of 10% palladium on carbon wascarefully added. The solution was charged with 50 psig hydrogen and wasvigorously stirred for 2.5 hours. The catalyst was removed by filtrationand the solution was concentrated to yield 849 mg (96% yield) of pureamine which has the following formula:

Part B

N-(2-quinolinylcarbonyl)-L-isoasparagine (366 mg, 1.2 mmol) wasdissolved in 4.0 mL of dry dimethylformamide, and to this was added 250mg (1.8 mmol) of N-hydroxybenzotriazole. After the solution washomogeneous, 230 mg (1.2 mmol) of1-(3-dimethyaminopropyl)-3-ethylcarbodiimide was added and the reactionstirred for 15 minutes. A solution of 510 mg (1.2 mmol) of amine frompart A was added in 4.0 mL of dimethylformamide to the solution andstirred for 16 hours. The majority of solvent was removed and replacedwith ethyl acetate. The organic phase was extracted with water,saturated sodium bicarbonate and concentrated to yield 693 mg of whitefoam. Flash chromatography on silica gel using a gradient elution from5% to 10% methanol/dichloromethane gave 346 mg of pure product,identified as butanediamide,N⁴-[3-[3-[[(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]-2-[(2-quinolinylcarbonyl)-amino]-,[3S-[2[1R*(R*),2S*],3α,4aβ,8aβ]]-.M+Li=677.3. Formula:

EXAMPLE 11 Preparation of N-(2-Quinolinylcarbonyl)-L-isoasparagine

To a solution of 0.50 g (3.78 mmol) of L-isoasparagine in 5.0 mL H₂Ocontaining ˜45 mg (1.5 eq) of solid bicarbonate. To this was added asuspension of 1.02 g (3.78 mmol) quinaldic acid, N-hydroxysuccinamideester in ethylene glycol dimethylether, and the suspension wassolubilized by the addition of 10 mL of dimethylformamide. After 3 hoursthe solution was acidified by the addition of 5% HCl (aqueous) and theproduct was filtered and washed with water, dried under vacuum to yield750 mg (70% yield) of N-(2-quinolinylcarbonyl)-L-isoasparagine.

Succinamide Derivatives EXAMPLE 12 Preparation of Butanamide,4-[[3-[3-[[(1,1-dimethylethyl)-amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]amino]-2,2,3-trimethyl-4-oxo-,[3S-[2[1R*(S*),2S*],3α,4aβ,8aβ]]-

Part A

A solution of carbamic acid,[3-[3-1[(1,1-dimethylethyl)amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]-,phenylmethyl ester, [3S-[2(1R*,2S*),3α,4 aβ,8aβ]]-(1.2 g, 2.2 mmol) wasdissolved in 50 mL of methanol and charged to a Fisher Porter tube. Thecontents were purged with nitrogen and 300 mg, 25 wt % of 10% palladiumon carbon was carefully added. The solution was charged with 50 psighydrogen and was vigorously stirred for 2.5 hours. The catalyst wasremoved by filtration and the solution was concentrated to yield 849 mg(96% yield) of pure amine having the following formula:

Part B

To a solution of benzyl 2,2,3(R)-trimethylsuccinate (125 mg, 0.5 mmol)in DMF (1.5 mL) was added HOBt (153 ma, 1.0 mmol). After all the solidwas dissolved, the solution was cooled to 0° C. and to this was addedEDC (143 ma, 0.75 mmol) and stirring was continued to 2 hours at 0° C.To this cold solution was added 200 mg (0.5 mmol) of amine from part Aand stirred at 0° C. for 2 hours and room temperature for 32 hours. Thesolvents were removed in vacuo (less than or equal to 40° C.) and theresidue was dissolved in ethyl acetate (5 mL). This solution was washedwith 60% sat. NaHCO₃ (2 mL×2), 5% citric acid (2 mL) and sat. NaCl (2mL×2). The combined organic layers were dried (Na₂SO₄) and concentratedto give a white solid. The purification of the crude product by flashchromatography (silica gel, 4% MeOH/CH₂Cl₂) gave 188 mg (59%) of thedesired product as a white solid, [M+Li]⁺=640, identified as butanoicacid,4-[[3-[3-[3-[[1,1-dimethylethyl)amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]amino]-2,2,3-trimethyl-4-oxo-,phenylmethyl ester, [3S-[2[1R*(S*),2S*],3α,4aβ,8a β]]-; formula:

Part C

A mixture of benzyl ester from part B (180 mg, 0.284 mmol), 10% Pd/C(125 mg) in methanol (MeOH) (2 mL) was hydrogenated (H₂, 50 psi) at roomtemperature for 30 minutes. The solid was filtered and was washed withMeOH (3 mL×2). The combined filtrates were concentrated to give 122 mg(79%) acid as a pale yellow solid, [M+H]⁺=544 and [M+Li]⁺=550,identified as butanoic acid,4-[(3-[3-[[(1,1-dimethylethyl)amino]carbonyl]octahydro-2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]amino]-2,2,3-trimethyl-4-oxo-,[3S-[2[1R*(S*),2S*],3α,4aβ,8β]]-;formula:

Part D

To a solution of acid from part C (120 ma, 0.22 mmol) in DMF (0.5 mL)was added HOBt (68 ma, 0.44 mmol), NH₄Cl (11.8 ma, 0.22 mmol) at roomtemperature. After all the solid was dissolved, to the solution wasadded LDC (63 ma, 0.33 mmol) at 0° C. and stirred at the temperature for2 hours. To this cold solution was added 30% NH₄OH (0.124 mL, 1.1 mmol)dropwise and the resulting mixture was stirred at 0° C. for 6 hours andat room temperature for 16 hours. The solvents were removed in vacuo(less than or equal to 40° C.) and the residue was dissolved in ethylacetate (5 mL). The solution was washed with 60% sat. NaHCO₃ (2 mL×2),5% citric acid (2 mL) and sat. NaCl (2 mL×2). The combined organiclayers were dried (Na₂SO₄) and concentrated to give a white solid. Thepurification of crude product by flash chromatography (silica gel, 5%MeOH/CH₂Cl₂) gave 72 mg (60%) of pure amide, [M+H]=543, identified asPreparation of Butanamide,4-[[3-[3-[[(1,1-dimethylethyl)amino]carbonyl]octahydro]2(1H)-isoquinolinyl]-2-hydroxy-1-(phenylmethyl)propyl]amino]-2,2,3-trimethyl-4-oxo-,[3S-[2[1R*(S*),2S*],3α,4aβ,8aβ]]-;formula:

In Example 12, part B, the benzyl 2,2,3(R)-trimethylsuccinate (seeExample 13 for preparation) may be substituted by the varioussuccinates, succinamides and itaconamides produced in Examples 513through 20 infra. in the appropriate amounts the determination of whichis within the skill of the art.

EXAMPLE 13 Preparation of Benzyl 2,2,3(R)-trimethylsuccinate

Part A: Preparation of Methyl (S)-lactate, 2-methoxy-2-propyl ether

To a mixture of methyl-(S)-(−)-lactate (13.2 g, 100 mmol) and2-methoxypropene (21.6 g, 300 mmol) in CH₂Cl₂ (150 mL) was added POCl₃(about 1.5 mL) at room temperature and the resulting mixture was stirredat this temperature for 16 hours. After the addition of triethylamine(NEt₃) (about 2 mL), the solvents were removed in vacuo to give 20.0 gof (98%) desired product.

Part B: Preparation of 2(S)-hydroxypropanal, 2-methoxy-2-propyl ether

To a solution of compound from Part A (20.0 g) in CH₂Cl₂ (100 mL) wasadded diisobutyl aluminum hydride (DIBAL) (65 mL of 1.5M solution intoluene, 97.5 mmol) dropwise at −78° C. for 45 minutes, then stirringwas continued at the temperature for another 45 minutes. To this coldsolution was added MeOH (20 mL), saturated NaCl solution (10 mL) andallowed the reaction mixture to warm up to room temperature and dilutedwith ether (200 mL), MgSO₄ (lSOg) was added and stirred for another 2hours. The mixture was filtered and the solid was washed twice withether. The combined filtrates were rotavaped to afford 11.2 g (78%) ofthe desired aldehyde.

Part C: Preparation of 2(S)-hydroxy-cis-3-butene, 2-methoxy-2-propylether

To a suspension of ethyltriphenylphosphonium bromide (28 g, 75.5 mmol)in THF (125 mL) was added potassium bis(trimethylsilyl)amide (KN(TMS)₂)(15.7 g, 95%, 75 mmol) in portions at 0° C. and stirred for 1 hour atthe temperature. This red reaction mixture was cooled to −78° C. and tothis was added a solution of aldehyde from Part B (11 g, 75 mmol) in THF(25 mL). After the addition was completed, the resulting reactionmixture was allowed to warm up to room temperature and stirred for 16hours. To this mixture was added saturated NH₄Cl (7.5 mL) and filteredthrough a pad of celite with a thin layer of silica gel on the top. Thesolid was washed twice with ether. The combined filtrates wereconcentrated in vacuo to afford 11.5 g of crude product. Thepurification of crude product by flash chromatography (silica gel, 10:1Hexanes/ethyl acetate) affording 8.2 g (69%) pure alkene.

Part D: Preparation of 2(S)-hydroxy-cis-3-butene

A mixture of alkene from Part C (8.2 g) and 30% aqueous acetic acid (25mL) was stirred at room temperature for 1 hour. To this mixture wasadded NaHCO₃ slowly to the pH˜7, then extracted with ether (10 mL×5).The combined ether solutions were dried (Na₂SO₄) and filtered. Thefiltrate was distilled to remove the ether to give 2.85 g (64%) purealcohol, m/e=87(M+H).

Part E: Preparation of 2,2,3-trimethyl-hex-(trans)-4-enoic acid

To a mixture of alcohol from Part D (2.5 g, 29 mmol) and pyridine (2.5mL) in CH₂Cl₂ (60 mL) was added isobutyryl chloride (3.1 g, 29 mmol)slowly at 0° C. The resulting mixture was stirred at room temperaturefor 2 hours then washed with H₂O (30 mL×2) and sat. NaCl (25 mL). Thecombined organic phases were dried (Na₂SO₄), concentrated to afford 4.2g (93%) ester 2(S)-hydroxy-cis-3-butenyl isobutyrate. This ester wasdissolved in THF (10 mL) and was added to a 1.0M lithiumdiisopropylamide (LDA) solution (13.5 mL of 2.0M LDA solution in THF and13.5 mL of THF) slowly at −78° C. The resulting mixture was allowed towarm up to room temperature and stirred for 2 hours and diluted with 5%NaOH (40 mL). The organic phase was separated, the aqueous phase waswashed with Et₂O (10 mL). The aqueous solution was collected andacidified with 6N HCl to pH ˜3. The mixture was extracted with ether (30mL×3). The combined ether layers were washed with sat. NaCl (25 mL),dried (Na₂SO₄) and concentrated to afford 2.5 g (60%) of desired acid,m/e=157 (M+H)

Part F: Preparation of benzyl 2,2,3(S)-trimethyl-trans-4-hexenoate

A mixture of acid from Part E (2.5 g, 16 mmol), benzylbromide (BnBr)(2.7 g, 15.8 mmol), K₂CO, (2.2 g, 16 mmol), NaI (2.4 g) in acetone (20mL) was heated at 75° C. (oil bath) for 16 hours. The acetone wasstripped off and the residue was dissolved in H₂O (25 mL) and ether (35mL). The ether layer was separated, dried (Na₂SO₄) and concentrated toafford 3.7 g (95%) of benzyl ester, m/e=247(M+H).

Part G: Preparation of benzyl 2,2,3(R)-trimethylsuccinate

To a well-stirred mixture of KMnO₄ (5.4 g, 34, 2 mmol), H₂O (34 mL),CH₂Cl₂ (6 mL) and benzyltriethylammonium chloride (200 mg) was added asolution of ester from Part F (2.1 g, 8.54 mmol) and acetic acid (6 mL)in CH₂Cl₂ (28 mL) slowly at 0° C. The resulting mixture was stirred atthe temperature for 2 hours then room temperature for 16 hours. Themixture was cooled in an ice-water bath, to this was added 6N HCl (3 mL)and solid NaHSO₃ in portions until the red color disappeared. The clearsolution was extracted with CH₂Cl₂ (30 mL×3). The combined extracts werewashed with sat. NaCl solution, dried (Na₂SO₄) and concentrated to givean oil. This oil was dissolved in Et₂O (50 mL) and to this was addedsat. NaHCO₃ (50 mL). The aqueous layer was separated and acidified with6N HCl to pH about 3 then extracted with Et₂O (30 mL×3). The combinedextracts were washed with sat. NaCl solution (15 mL), dried (Na₂SO₄) andconcentrated to afford 725 mg (34%) of desired acid, benzyl2,2,3(R)-trimethylsuccinate, m/e=251 (M+H).

EXAMPLE 14 Preparation of methyl 2,2-dimethyl-3-methyl succinate, (R)and (S) isomers

Part A: Preparation of methyl 2,2-dimethyl-3-oxo-butanoate

A 250 mL RB flask equipped with magnetic stir bar and N2 inlet wascharged with 100 mL dry THF and 4.57 g (180 mmol) of 95% NaH. The slurrywas cooled to −20° C. and 10 g (87 mmol) methyl acetoacetate was addeddropwise followed by 11.3 mL (181 mmol) CH₃I. The reaction was stirredat 0° C. for 2 hours and let cool to room temperature overnight. Thereaction was filtered to remove NaI and diluted with 125 mL Et₂O. Theorganic phase was washed with 1×100 L 5% brine, dried and concentratedin vacuo to a dark golden oil that was filtered through a 30 g plug ofsilica gel with hexane. Concentration in vacuo yielded 10.05 g ofdesired methyl ester, as a pale yellow oil, suitable for use withoutfurther purification.

Part B: Preparation of methyl2,2-dimethyl-3-O-(trifluoromethanesulfonate)-but-3-eneoate

A 250 ml RB flask equipped with magnetic stir bar and N₂ inlet wascharged with 80 mL by THP and 5.25 mL (37.5 mmol) diisopropylamine wasadded. The solution was cooled to −25° C. (dry ice/ethylene glycol) and15 mL (37.5 mmol) of 2.5 M n-butyl lithium (n-BuLi) in hexanes wasadded. After 10 minutes a solution of 5 g (35 mmol) of methyl2,2-dimethyl-3-oxo-butanoate from Part A in 8 mL dry THF was added. Thedeep yellow solution was stirred at −20° C. for 10 minutes then 12.4 gN-phenyl-bis(trifluoromethanesulfonimide) (35 mmol) was added. Thereaction was stirred at about −10° C. for 2 hours, concentrated in vacuoand partitioned between ethyl acetate and sat. nacho. The combinedorganic phase was washed with NaHCO₃, brine and concentrated to an amberoil that was filtered through 60 g silica gel plug with 300 mL 5% ethylacetate/hexane. Concentration in vacuo yielded 9.0 g light yellow oilthat was diluted with 65 mL ethyl acetate and washed with 2×50 mL 5% aq.K₂CO₃, 1×10 mL brine, dried over Na₂SO₄ and concentrated in vacuo toyield 7.5 g (87%) vinyl triflate, (m/e=277(M+H) suitable for use withoutfurther purification.

Part C: Preparation of methyl 2,2-dimethyl-3-carboxyl-but-3-enoate

A 250 mL Fisher Porter bottle was charged with 7.5 g (27 mmol) ofcompound prepared in Part B, 50 mL dry DMF, 360 mg (1.37 mmol) triphenylphosphine and 155 mg (0.69 mmol) palladium (II) acetate. The reactionmixture was purged twice with N₂ then charged with 30 psig CO. Meanwhilea solution of 20 mL dry DMF and 7.56 mL (54 mmol) NEt₃ was cooled to 0°C. to this was added 2.0 g (43 mmol) of 99% formic acid. The mixture wasswirled and added to the vented Fisher Porter tube. The reaction vesselwas recharged to 40 psig of CO and stirred 6 hours @ room temperature.The reaction mixture was concentrated in vacuo and partitioned between100 mL of ethyl acetate and 75 mL 5% aq. K₂CO₃. The aqueous phase waswashed with 1×40 mL additional ethyl acetate and then acidified withconcentrated HCl/ice. The aqueous phase was extracted with 2×70 mL ofethyl acetate and the organics were dried and concentrated to yield 3.5g (75%) white crystals, mp 72-75° C., identified as the desired product(m/e=173(M+H).

Part D: Preparation of methyl 2,2-dimethyl-3-methylsuccinate, isomer #1

A steel hydrogenation vessel was charged with 510 mg (3.0 mmol) acrylicacid, from Part C, and 6 mg Ru (acac)₂ (R-BINAP) in 10 ml degassed MeOH.The reaction was hydrogenated at 50 psig/room temperature for 12 hours.The reaction was then fltered through celite and concentrated to 500 mgclear oil which was shown to be a 93:7 mixture of isomer #1 and #2,respectively as determined by GC analysis using a 50 M, B-cyclodextrincolumn (chiral GC): 150° C.-15 min. then ramp 2° C./min.; isomer #1,17.85 minute retention time, isomer #2, 18-20 minute retention time.

Part E: Preparation of methyl 2,2-dimethyl-3-methylsuccinate, Isomer #2

A steel hydrogenation vessel was charged with 500 mg (2.9 mmol) acrylicacid, Part C, and 6 mg Ru(OAc) (acac) (S-BINAP) in 10 mL degassed MeOH.The reaction was hydrogenated at 50 psig/room temperature for 10 hours.The reaction was filtered through celite and concentrated in vacuo toyield 490 mg of product as a 1:99 mixture of isomers #1 and #2,respectively, as determined by chiral GC as above.

EXAMPLE 15 Preparation of Chiral Succinamides from Itaconic AnhydridePart A: Preparation of 4-N-benzyl itaconamide

A 500 mL three necked round bottomed flask equipped with a droppingfunnel, mechanical stirrer, nitrogen inlet and reflux condenser wascharged with itaconic anhydride (33.6 g, 0.3 mol) and 150 mL of toluene.This solution was added a solution of benzylamine (32. la, 0.3 mol) in50 mL of toluene dropwise over 30 minutes at room temperature. Thesolution was stirred at this temperature an additional 3 hours and thenthe solid product isolated by fltration on a Buchner funnel. The crudeproduct, 64.6 g, 98%, was recrystallized from 300 mL of isopropylalcohol to give after two crops 52.1 g, 79% of pure product, mp 149150°C.

Part B: Preparation of 2(R)-Methyl 4-N-benzyl succinamide

A large Fisher-Porter bottle was charged with the acid from the abovereaction (10.9Sg, 0.05 mol), rhodium (R,R)-DiPAMP (220 mg, 0.291 mmol)and 125 mL of degassed methanol. The solution was then hydrogenated at40 psig for 16 hours at room temperature. After the hydrogen uptakeceased, the vessel was opened and the solution concentrated in vacuo togive a yellow solid, 11.05 g, 100%. The product was then taken up inabsolute ethanol and allowed to stand whereupon crystals of the desiredproduct formed, 7.98 g, 72%, mp 127-129° C., [a]D @ 25° C.=+14.9°(c=1.332, EtOH), ¹H NMR (CDCl+) 300 MHz 7.30(m,5H), 6.80(brs, 1H),4.41(d, J=5.8 Hz, 2H), 2.94(m, 1H), 2.62(dd, J=8.1, 14.9 Hz, 1H),2.33(dd, J=5.5, 14.9 Hz, 1H), 1.23(d, J=7.2 Hz, 3H).

Part C: Preparation of 4-N(4-methoxybenzyl)itaconamide

A 500 mL three necked round bottomed flask equipped with a droppingfunnel, mechanical stirrer, nitrogen inlet and reflux condenser wascharged with itaconic anhydride (44.8 g, 0.4 mol) and 150 ml of toluene.This solution was added a solution of 4-methoxybenzylamine (54.8 g, 0.4mol) in 50 mL of toluene dropwise over 30 minutes at room temperature.The solution was stirred at this temperature an additional 2 hours andthen the solid product isolated by filtration on a Buchner funnel. Thecrude product was recrystallized from ethyl acetate/ethanol to giveafter two crops 64.8 g, 65% of pure product, mp 132-134° C., ¹H nmr(CDCl₃) 300 MHz 7.09(d, J=9.1 Hz, 2H), 6.90(brt, J=5.9 Hz, 1H), 6.74(d,J=9.1 Hz, 2H), 6.22(s, 1H), 5.69(s, 1H), 4.24(d, J=5.9 Hz, 2H),3.69(s,3H), 3.15(s, 2H). ¹³C nmr (CDCl₃) 170.52, 169.29, 159.24, 135.61,131.08, 129.37, 128.97, 114.36, 55.72, 43.37, 40.58.

Part D: Preparation of 2(R)-Methyl-4-N(4-methoxybenzyl)succinamide

A large Fisher-Porter bottle was charged with the acid from the abovereaction (5.00 g, 0.02 mol), rhodium (R,R)-DiPAMP (110 mg, 0.146 mmol)and 50 mL of degassed methanol. The starting acid was not completelysoluble initially, but as the reaction progressed the solution becamehomogeneous. The solution was then hydrogenated at 40 psig for 16 hoursat room temperature. After the hydrogen uptake ceased, the vessel wasopened and the solution concentrated in vacuo to give a yellow solid.The crude product was then taken up in ethyl acetate and washed threetimes with sat. aq. NaHCO₃ solution. The combined aqueous extracts wereacidified to pH=1 with 3 N HCl and then extracted three times with ethylacetate. The combined ethyl acetate extracts were washed with brine,dried over anhyd. MgSO₄, filtered and concentrated to give the expectedproduct as a white solid, 4.81 g, 95%. This material was recrystallizedfrom a mixture of methyl ethyl ketone/hexane to give 3.80 g, 75% of pureproduct, [a]_(D) @ 25° C.=+11.6° (c=1.572, MeOH). H nmr (CDCl₃) 300 MHz11.9(brs,1H), 7.18(d, J=9.2 Hz, 2H), 6.82(d, J=9.2 Hz, 2H), 6.68(brt,J=5.6 Hz, 1H), 4.33(d, J=5.6 Hz, 2H), 3.77(s, 3H), 2.92(ddq, J=7.9, 5.4,7.3 Hz, 1H), 2.60(dd, J=5.4, 15.0 Hz, 1H), 2.30(dd, J=7.9, 15.0 Hz,1H),1.22(d, J=7.3 Hz, 3H).

EXAMPLE 16 Preparation of Trans-mono-ethyl 1,2-Cyclopropanedicarboxylate

To a solution of 4.60 g (24.7 mmol) oftrans-diethyl-1,2-cyclopropanedicarboxylate in 100 mL of 50:50 v:vtetrahydrofuran/water was added 1.24 g (29.6 mmol) of lithium hydroxide.After 17 hours, the tetrahydrofuran was removed in vacuo, the waterlayer washed with ethyl acetate, acidified with 1N hydrochloric acid andreextracted with ethyl acetate. The organic layer was dried and strippedto afford 2.1 g of crude product. After recrystallization fromdiethylether/hexane and then methylene chloride/hexane, one obtains 1.1g (28%) of trans-monoethyl-1,2-cyclopropanedicarboxylate, m/e=159 (M+H).

EXAMPLE 17 Preparation of 2(R)-Methyl-4-benzyl Succinate Part A

To a suspension of 24.7 g (0.22 mol) of itaconic anhydride in 100 mL ofanhydrous toluene at reflux under a nitrogen atmosphere was addeddropwise over 30 minutes 23.9 g (0.22 mol) of benzyl alcohol. Theinsoluble material dissolved to provide a homogeneous solution which wasrefluxed for 1.5 hours. The solution was cooled to room temperature,then in an ice bath and the resulting white precipitate collected byfiltration to afford 24.8 g (51%) of 4-benzyl itaconate.

Part B

To a solution of 2.13 g (9.5 mmol) of the product from Part A in 12 mLof methylene chloride at 0° C. was added 4.02 g (29.1 mmol) ofpara-methoxybenzyl alcohol, 605 mg (4.95 mmol) ofN,N-dimethyl-4-aminopyridine, 128 mg of N,N-dimethyl-4-aminopyridinehydrochloride salt and then 2.02 g (4.7 mmol) dicyclohexylcarbodiimide(DCC). After stirring at 0° C. for 1 hour and then room temperature for2 hours, the precipitate was collected and discarded. The filtrate waswashed with 0.5 N HCl, sat. NaHCO₃, dried and stripped to afford 4.76 gof crude product. This was chromatographed on silica gel using 0-50%ethyl acetate/hexane to afford 1.24 g of pure4′-methoxybenzyl-4-benzylitaconate.

Part C

A solution of 1.24 g (3.65 mmol) of product from Part B and 20 mg of[(R,R)-DiPAMP)cyclooctadienylrhodium] tetrafluoroborate in 30 mL ofmethanol was thoroughly degassed, flushed with nitrogen and thenhydrogen and then stirred under 50 psig of hydrogen for 15 hours. Thesolution was filtered and stripped, dissolved in methylene chloride andwashed with sat. NaHCO₃, dried and stripped to afford 0.99 g of a brownoil. This was then dissolved in 40 mL of methylene chloride, 3 mL oftrifluoroacetic acid added and the solution stirred at room temperaturefor 3.5 hours. Water was added and separated and the organic layerextracted with sat. NaHCO₃. The aqueous layer was acidified andreextracted with ethyl acetate, separated and the organic layer washedwith brine, dried and stripped to afford 320 mg (50%) of2(R)-methyl-4-benzylsuccinic acid.

EXAMPLE 18 Preparation of 2(S)-Methyl-4-benzyl Succinate

A solution of 1.41 g (4.1 mmol) of 4′-methoxybenzyl-4-benzylitaconateand 25 mg of [(S,S-DiPAMP)cyclooctadienyl-rhodium]tetrafluoroborate in20 mL of methanol was thoroughly degassed, flushed with nitrogen andthen hydrogen and then stirred under 40 psig hydrogen for 72 hours. Thesolution was filtered and concentrated to provide 1.34 g of a brown oil.This was dissolved in 40 mL of methylene chloride and 3 mL oftrifluoroacetic acid was added. After stirring for 4 hours, water wasadded, separated and the organic layer extracted with sat. NaHCO₃. Theaqueous layer was separated, reacidified, extracted with ethyl acetatewhich was separated, washed with brine, dried and stripped to afford 440mg of 2(S)-methyl-4-benzylsuccinic acid (also known as,2(S)-Methyl-4-benzyl succinate).

EXAMPLE 19 Preparation of 3(R)-Methyl-4-benzyl Succinate Part A

In a similar manner to the procedure used above in Example 17, Part A,p-methoxybenzyl alcohol was reacted with itaconic anhydride in refluxingtoluene to provide 4-(p-methoxybenzyl)itaconate.

Part B

To a solution of 3.30 g (13.2 mmol) of the product from Part A in 17 mLof toluene, was added 2.08 g (13.7 mmol) of 1,8diazabicyclo[5.4.0]undec-7-ene and then 2.35 g (13.7 mmol) of benzylbromide. After 2 hours, the solution was fltered and the filtrate washedwith sat. NaHCO₃, 3N HCl, brine, dried and concentrated to afford 3.12 gof an oil. After chromatography on silica gel using 0-5% ethylacetate/hexane one obtains 2.19 g (49%) of benzyl 4-(4-methoxybenzyl)itaconate.

Part C

A solution of 1.22 g (3.6 mmol) of product from Part B and 150 mg of[((R,R-DiPAMP)) cyclooctadienylrhodium] tetrafluoroborate in 15 mL ofmethanol was thoroughly degassed, flushed with nitrogen and thenhydrogen and hydrogenated under 50 psig for 16 hours. The solution wasfiltered and concentrated to afford 1.2 g of a brown oil. This wasdissolved in 5 mL of methylene chloride and 5 mL of toluene and 3 mL oftrifluoroacetic acid was added. After 4 hours, the solvents were removedin vacuo, the residue dissolved in methylene chloride, which was thenextracted with sat. NaHCO₃. After separation, the aqueous layer wasacidified, reextracted with methylene chloride which was then dried andconcentrated to afford 470 mg (60%) of 3(R)-methyl-4-benzylsuccinic acid(also known as, 3(R)-methyl-4-benzyl succinate).

EXAMPLE 20 Preparation of 3(S)-Methyl-4-benzyl Succinate

This was prepared in an identical manner to the previous example(Example 19) except that the asymmetric hydrogenation step was done inthe presence of [((S,S-DiPAMP)cyclooctadienyl)rhodium]-tetrafluoroborateas catalyst.

EXAMPLE 21

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 22

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 23

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 24

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 25

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 26

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 27

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 28

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 29

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 30

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 31

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 32

The compound of this example is prepared using methods illustrated andreferred to hereinabove.

EXAMPLE 33 Assays Part A: Enzyme Assay

Utilizing an enzyme assay as described below, the compounds set forth inExamples 4, 6, 10, 12 and 12C inhibited the HIV enzyme in an amountranging from about 3 to about 100% inhibition at a concentration of 10microMolar. The calculated IC₅₀ (inhibiting concentration 50%, i.e., theconcentrations at which the inhibitor compound reduces enzyme activityby 50%) values are shown in Table 1. The enzyme method is describedbelow. The substrate is 2-aminobenzoyl-Ile-Nle-phe(p-NO2)-Gln-ArgNH2.The positive control is MVT-101 (Miller, M. et al, Science, 246, 1149(1989)] The assay conditions are as follows:

-   Assay buffer: 20 mM sodium phosphate, pH 6.4-   20% glycerol-   1 mM EDTA-   1 mM DTT-   0.1% CHAPS

The above described substrate is dissolved in DMSO, then diluted 10 foldin assay buffer. Final substrate concentration in the assay is 80 μM.

HIV protease is diluted in the assay buffer to a final enzymeconcentration of 12.3 nanomolar, based on a molecular weight of 10,780.

The final concentration of DMSO is 14% and the final concentration ofglycerol is 18%. The test compound is dissolved in DMSO and diluted inDMSO to 10× the test concentration; 10 μL of the enzyme preparation isadded, the materials mixed and then the mixture is incubated at ambienttemperature for 15 minutes. The enzyme reaction is initiated by theaddition of 40 μL of substrate. The increase in fluorescence ismonitored at 4 time points (0, 8, 16 and 24 minutes) at ambienttemperature. Each assay is carried out in duplicate wells.

Part B: CEM Cell Assay

The effectiveness of the compounds tested in Part A was also determinedin a CEM cell assay. The HIV inhibition assay method of acutely infectedcells is an automated tetrazolium based calorimetric assay essentiallythat reported by Pauwles et al, J. Virol. Methods 20, 309-321 (1988).Assays were performed in 96-well tissue culture plates. CEM cells, aCD4⁺ cell line, were grown in RPMI-1640 medium (Gibco) supplemented witha 10% fetal calf serum and were then treated with polybrene (2 pg/mL).An 80 μL volume of medium containing 1×10⁴ cells was dispensed into eachwell of the tissue culture plate. To each well was added a 100 μL volumeof test compound dissolved in tissue culture medium (or medium withouttest compound as a control) to achieve the desired final concentrationand the cells were incubated at 37° C. for 1 hour. A frozen culture ofHIV-1 was diluted in culture medium to a concentration of 5×10⁴ TCID₅₀per mL (TCID₅₀=the dose of virus that infects 50% of cells in tissueculture), and a 20 μL volume of the virus sample (containing 1000 TCID₅₀of virus) was added to wells containing test compound and to wellscontaining only medium (infected control cells). Several wells receivedculture medium without virus (uninfected control cells). Likewise, theintrinsic toxicity of the test compound was determined by adding mediumwithout virus to several wells containing test compound. In summary, thetissue culture plates contained the following experiments: Cells DrugVirus 1. + − − 2. + + − 3. + − + 4. + + +

In experiments 2 and 4, the final concentrations of test compounds were1, 10, 100 and 500 μg/mL. Either azidothymidine (AZT) or dideoxyinosine(ddI) was included as a positive drug control. Test compounds weredissolved in DMSO and diluted into tissue culture medium so that thefinal DMSO concentration did not exceed 1.5% in any case. DMSO was addedto all control wells at an appropriate concentration.

Following the addition of virus, cells were incubated at 37° C. in ahumidified, 5% CO₂ atmosphere for 7 days. Test compounds could be addedon days 0, 2 and 5 if desired. On day 7, post-infection, the cells ineach well were resuspended and a 100 μL sample of each cell suspensionwas removed for assay. A 20 L volume of a 5 mg/mL solution of3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) wasadded to each 100 μL cell suspension, and the cells were incubated for 4hours at 27° C. in a 5% CO2 environment. During this incubation, MTT ismetabolically reduced by living cells resulting in the production in thecell of a colored formazan product. To each sample was added 100 pL of10% sodium dodecylsulfate in 0.01 N HCl to lyse the cells, and sampleswere incubated overnight. The absorbance at 590 nm was determined foreach sample using a Molecular Devices microplate reader. Absorbancevalues for each set of wells is compared to assess viral controlinfection, uninfected control cell response as well as test compound bycytotoxicity and antiviral efficacy.

The calculated EC₅₀ (effective concentration 50%, i.e., theconcentration at which the inhibitor compound reduces cytopathicity by50%) and TD₅₀ (toxic dose 50%, i.e., the concentration at which theinhibitor compound reduces cellular viability by 50%) values for thesecompounds are also shown in Table 1. TABLE 1 Antiviral Activity Enzymein Cell Cell Inhibition Culture Toxicity Structure (IC₅₀) (EC₅₀) (TD₅₀)

 7 nM  42 nM 58,000 nM

 2 nM  52 nM  2,000 nM

 9 nM  37 nM  5,000 nM

 9 nM  98 nM 59,000 nM

23 nM 184 nM 50,000 nM

It is expected that compounds of Formulae I-IV would be active whentested in the assays described in Example 33 above.

The compounds of the present invention can be used in the form of saltsderived from inorganic or organic acids. These salts include but are notlimited to the following: acetate, adipate, alginate, citrate,aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, camphorate,camphorsulfonate, digluconate, cyclopentanepropionate, dodecylsulfate,ethanesulfonate, glucoheptanoate, glycerophosphate, hemisulfate,heptanoate, hexanoate, fumarate, hydrochloride, hydrobromide,hydroiodide, 2-hydroxy-ethanesulfonate, lactate, maleate,methanesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate, palmoate,pectinate, persulfate, 3-phenylpropionate, picrate, pivalate,propionate, succinate, tartrate, thiocyanate, tosylate, mesylate andundecanoate. Also, the basic nitrogen-containing groups can bequaternized with such agents as lower alkyl halides, such as methyl,ethyl, propyl, and butyl chloride, bromides, and iodides; dialkylsulfates like dimethyl, diethyl, dibutyl, and diamyl sulfates, longchain halides such as decyl, lauryl, myristyl and stearyl chlorides,bromides and iodides, aralkyl halides like benzyl and phenethylbromides, and others. Water or oil-soluble or dispersible products arethereby obtained.

Examples of acids which may be employed to form pharmaceuticallyacceptable acid addition salts include such inorganic acids ashydrochloric acid, sulphuric acid and phosphoric acid and such organicacids as oxalic acid, maleic acid, succinic acid and citric acid. Otherexamples include salts with alkali metals or alkaline earth metals, suchas sodium, potassium, calcium or magnesium or with organic bases.

Total daily dose administered to a host in single or divided doses maybe in amounts, for example, from 0.001 to 10 mg/kg body weight daily andmore usually 0.01 to 1 ma. Dosage unit compositions may contain suchamounts of submultiples thereof to make up the daily dose.

The amount of active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration.

The dosage regimen to give relief from or ameliorate a disease condition(i.e., treatment) or protecting against the further spreading of theinfection (i.e., prophylaxis) with the compounds and/or compositions ofthis invention is selected in accordance with a variety of factors,including the type, age, weight, sex, diet and medical condition of thepatient, the severity of the disease, the route of administration,pharmacological considerations such as the activity, efficacy,pharmacokinetic and toxicology profiles of the particular compoundemployed, whether a drug delivery system is utilized and whether thecompound is administered as part of a drug combination. Thus, the dosageregimen actually employed may vary widely and therefore deviate from thepreferred dosage regimen set forth above.

The compounds of the present invention may be administered orally,parenterally, by inhalation spray, rectally, or topically in dosage unitformulations containing conventional nontoxic pharmaceuticallyacceptable carriers, adjuvants, and vehicles as desired. Topicaladministration may also involve the use of transdermal administrationsuch as transdermal patches or iontophoresis devices. The termparenteral as used herein includes subcutaneous injections, intravenous,intramuscular, intrasternal injection, or infusion techniques.

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions may be formulated according to the known artusing suitable dispersing or wetting agents and suspending agents. Thesterile injectable preparation may also be a sterile injectable solutionor suspension in a nontoxic parenterally acceptable diluent or solvent,for example, as a solution in 1,3-butanedidol. Among the acceptablevehicles and solvents that may be employed are water, Ringer's solution,and isotonic sodium chloride solution. In addition, sterile, fixed oilsare conventionally employed as a solvent or suspending medium. For thispurpose any bland fixed oil may be employed including synthetic mono- ordiglycerides. In addition, fatty acids such as oleic acid find use inthe preparation of injectables.

Suppositories for rectal administration of the drug can be prepared bymixing the drug with a suitable nonirritating excipient such as cocoabutter and polyethylene glycols which are solid at ordinary temperaturesbut liquid at the rectal temperature and will therefore melt in therectum and release the drug.

Solid dosage forms for oral administration may include capsules,tablets, pills, powders, and granules. In such solid dosage forms, theactive compound may be admixed with at least one inert diluent such assucrose lactose or starch. Such dosage forms may also comprise, as innormal practice, additional substances other than inert diluents, e.g.,lubricating agents such as magnesium stearate. In the case of capsules,tablets, and pills, the dosage forms may also comprise buffering agents.Tablets and pills can additionaUy be prepared with enteric coatings.

Liquid dosage forms for oral administration may include pharmaceuticallyacceptable emulsions, solutions, suspensions, syrups, and elixirscontaining inert diluents commonly used in the art, such as water. Suchcompositions may also comprise adjuvants, such as wetting agents,emulsifying and suspending agents, and sweetening, flavoring, andperfuming agents.

Pharmaceutically acceptable carriers encompass all the foregoing and thelike.

While the compounds of the invention can be administered as the soleactive pharmaceutical agent, they can also be used in combination withone or more immunomodulators, antiviral agents or other antiinfectiveagents. For example, the compounds of the invention can be administeredin combination with AZT, other nucleoside antivirals, other HIV-proteaseinhibitors or with iminosugars such as N-butyl-1-deoxynojirimycin forthe prophylaxis and/or treatment of AIDS or HIV infection. Theadditional antiviral agents can be selected, if desired, usingphenotyping and/or genotyping methods to determinesensitivity/resistance parameters that can be used by the skilled personas an aid in the selection of the drug or drugs to be used incombination. Included in the possibilities of for combination therapyare drugs useful for the treatment of the secondary symptoms of HIVinfection, ARC or AIDS. When administered as a combination, thetherapeutic agents can be formulated as separate compositions which aregiven at the same time or different times, or the therapeutic agents canbe given as a single composition.

The foregoing is merely illustrative of the invention and is notintended to limit the invention to the disclosed compounds. Variationsand changes which are obvious to one skilled in the art are intended tobe within the scope and nature of the invention which are defined in theappended claims.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. A compound represented by the formula

wherein R′ represents a radical selected from the group consisting of ahydrogen radical, alkenyl, alkynyl, haloalkyl, hydroxyalkyl,alkoxyalkyl, cycloalkyl, cycloalkylalkyl, heterocycloalkyl, heteroaryl,heterocycloalkylalkyl, and heteroaralkyl; t is 0 or 1; R¹ represents aradical selected from the group consisting of a hydrogen radical,—CH₂SO₂NH₂, —CO₂CH₃, —CH₂CO₂CH₃, —C(O)NH₂, —C(O)NHCH₃, —C(O)N(CH₃)₂,—CH₂C(O)NHCH₃, —CH₂C(O)N(CH₃)₂, alkyl, alkylthioalkyl, thioalkyl, thecorresponding sulfoxide and sulfone derivatives of alkylthioalkyl andthioalkyl, alkenyl, alkynyl, alkoxyalkyl, haloalkyl, cycloalkyl, andamino acid side chains selected from the group consisting of asparagine,S-methyl cysteine and the corresponding sulfoxide and sulfonederivatives of S-methyl cysteine, glycine, leucine, isoleucine,allo-isoleucine, tert-leucine, alanine, phenylalanine, ornithine,histidine, norleucine, glutamine, valine, threonine, allo-threonine,serine, aspartic acid and beta-cyano alanine; Y′ represents O, S, andNR³, wherein R³ represents a radical selected from the group consistingof a hydrogen radical, alkyl, alkenyl, alkynyl, haloalkyl, hydroxyalkyl,alkoxyalkyl, cycloalkyl, cycloalkylalkyl, heterocycloalkyl, heteroaryl,heterocycloalkylalkyl, aryl, aralkyl, and heteroaralkyl radicals; R⁶represents a hydrogen radical or an alkyl radical; and R²⁰ and R²¹independently represent radicals as defined for R¹.
 2. A compound ofclaim 1 having the formula


3. A pharmaceutical composition comprising a compound of claim 1 and apharmaceutical carrier.
 4. A pharmaceutical composition comprising acompound of claim 1 and pharmaceutical carriers.
 5. A method ofinhibiting a retroviral protease comprising administering a proteaseinhibiting amount of a compound of claim 100.